Bug 1652098 - move linux base toolchain builds to their own file; r=dmajor

The explanatory comment at the top of the new file provides some context.
The larger motivating context here is wanting to use `job-defaults` to clean
up the toolchain fetches for the Linux build jobs.  But if we did that, we
run into the problem that such fetches are merged with whatever the
individual job(s) specify for their toolchain fetches, not replaced.  So
we'd wind up with multiple clang toolchains being downloaded, or similar,
and things would go downhill from there, as workers attempt to unpack those
things to the same location (which is bad) or perhaps error out (which is
also bad).

This change therefore paves the way for providing `job-defaults` in linux.yml.

Differential Revision: https://phabricator.services.mozilla.com/D83158

taskcluster/ci/build/kind.yml

@@ -20,6 +20,7 @@ jobs-from:
     - android.yml
     - android-stuff.yml
     - linux.yml
+    - linux-base-toolchains.yml
     - macosx.yml
     - windows.yml
     - windows-mingw.yml

taskcluster/ci/build/linux-base-toolchains.yml

@@ -0,0 +1,167 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# We have these build jobs in a separate file because their definitions are
+# different enough from the main Linux build jobs that their presence in
+# linux.yml would make using job-defaults there significantly less useful.
+---
+linux64-base-toolchains/opt:
+    description: "Linux64 base toolchains Opt"
+    index:
+        product: firefox
+        job-name: linux64-base-toolchains-opt
+    treeherder:
+        platform: linux64/opt
+        symbol: Bb
+    run-on-projects: ['mozilla-central']
+    worker-type: b-linux
+    worker:
+        docker-image: {in-tree: debian8-amd64-build-base}
+        max-run-time: 7200
+        env:
+            MOZ_LOW_PARALLELISM_BUILD: '1'
+            PERFHERDER_EXTRA_OPTIONS: base-toolchains
+            FORCE_GCC: '1'
+    run:
+        using: mozharness
+        actions: [get-secrets, build]
+        config:
+            - builds/releng_base_firefox.py
+            - builds/releng_base_linux_64_builds.py
+        script: "mozharness/scripts/fx_desktop_build.py"
+        secrets: true
+        tooltool-downloads: public
+        need-xvfb: true
+    use-sccache: true
+    fetches:
+        toolchain:
+            - linux64-clang-5.0
+            - linux64-gcc-7
+            - linux64-rust-1.43
+            - linux64-cbindgen
+            - linux64-sccache
+            - linux64-nasm-2.14.02
+            - linux64-node
+
+linux64-base-toolchains/debug:
+    description: "Linux64 base toolchains Debug"
+    index:
+        product: firefox
+        job-name: linux64-base-toolchains-debug
+    treeherder:
+        platform: linux64/debug
+        symbol: Bb
+    optimization:
+        push-interval-10: null
+    worker-type: b-linux
+    worker:
+        docker-image: {in-tree: debian8-amd64-build-base}
+        max-run-time: 7200
+        env:
+            MOZ_LOW_PARALLELISM_BUILD: '1'
+            PERFHERDER_EXTRA_OPTIONS: base-toolchains
+            FORCE_GCC: '1'
+    run:
+        using: mozharness
+        actions: [get-secrets, build]
+        config:
+            - builds/releng_base_firefox.py
+            - builds/releng_base_linux_64_builds.py
+        script: "mozharness/scripts/fx_desktop_build.py"
+        secrets: true
+        custom-build-variant-cfg: debug
+        mozconfig-variant: debug
+        tooltool-downloads: public
+        need-xvfb: true
+    use-sccache: true
+    fetches:
+        toolchain:
+            - linux64-clang-5.0
+            - linux64-gcc-7
+            - linux64-rust-1.43
+            - linux64-cbindgen
+            - linux64-sccache
+            - linux64-nasm-2.14.02
+            - linux64-node
+            # `fix-stacks` is needed because xpcshell self tests run as part of
+            # the build step. Once bug 1614626 moves them to the xpcshell task,
+            # this dependency can be removed.
+            - linux64-fix-stacks
+
+linux64-base-toolchains-clang/opt:
+    description: "Linux64 base toolchains clang Opt"
+    index:
+        product: firefox
+        job-name: linux64-base-toolchains-clang-opt
+    treeherder:
+        platform: linux64/opt
+        symbol: Bbc
+    run-on-projects: ['mozilla-central']
+    worker-type: b-linux
+    worker:
+        docker-image: {in-tree: debian8-amd64-build-base}
+        max-run-time: 7200
+        env:
+            PERFHERDER_EXTRA_OPTIONS: base-toolchains-clang
+            DISABLE_CLANG_PLUGIN: '1'
+    run:
+        using: mozharness
+        actions: [get-secrets, build]
+        config:
+            - builds/releng_base_firefox.py
+            - builds/releng_base_linux_64_builds.py
+        script: "mozharness/scripts/fx_desktop_build.py"
+        secrets: true
+        tooltool-downloads: public
+        need-xvfb: true
+    fetches:
+        toolchain:
+            - linux64-binutils
+            - linux64-clang-5.0
+            - linux64-rust-1.43
+            - linux64-cbindgen
+            - linux64-nasm-2.14.02
+            - linux64-node
+
+linux64-base-toolchains-clang/debug:
+    description: "Linux64 base toolchains clang Debug"
+    index:
+        product: firefox
+        job-name: linux64-base-toolchains-clang-debug
+    treeherder:
+        platform: linux64/debug
+        symbol: Bbc
+    optimization:
+        push-interval-10: null
+    worker-type: b-linux
+    worker:
+        docker-image: {in-tree: debian8-amd64-build-base}
+        max-run-time: 5400
+        env:
+            PERFHERDER_EXTRA_OPTIONS: base-toolchains-clang
+            DISABLE_CLANG_PLUGIN: '1'
+    run:
+        using: mozharness
+        actions: [get-secrets, build]
+        config:
+            - builds/releng_base_firefox.py
+            - builds/releng_base_linux_64_builds.py
+        script: "mozharness/scripts/fx_desktop_build.py"
+        secrets: true
+        custom-build-variant-cfg: debug
+        mozconfig-variant: debug
+        tooltool-downloads: public
+        need-xvfb: true
+    fetches:
+        toolchain:
+            - linux64-binutils
+            - linux64-clang-5.0
+            - linux64-rust-1.43
+            - linux64-cbindgen
+            - linux64-nasm-2.14.02
+            - linux64-node
+            # `fix-stacks` is needed because xpcshell self tests run as part of
+            # the build step. Once bug 1614626 moves them to the xpcshell task,
+            # this dependency can be removed.
+            - linux64-fix-stacks

taskcluster/ci/build/linux.yml

@@ -307,166 +307,6 @@ linux64-devedition/opt:
             - linux64-lucetc
             - wasi-sysroot
 
-linux64-base-toolchains/opt:
-    description: "Linux64 base toolchains Opt"
-    index:
-        product: firefox
-        job-name: linux64-base-toolchains-opt
-    treeherder:
-        platform: linux64/opt
-        symbol: Bb
-    run-on-projects: ['mozilla-central']
-    worker-type: b-linux
-    worker:
-        docker-image: {in-tree: debian8-amd64-build-base}
-        max-run-time: 7200
-        env:
-            MOZ_LOW_PARALLELISM_BUILD: '1'
-            PERFHERDER_EXTRA_OPTIONS: base-toolchains
-            FORCE_GCC: '1'
-    run:
-        using: mozharness
-        actions: [get-secrets, build]
-        config:
-            - builds/releng_base_firefox.py
-            - builds/releng_base_linux_64_builds.py
-        script: "mozharness/scripts/fx_desktop_build.py"
-        secrets: true
-        tooltool-downloads: public
-        need-xvfb: true
-    use-sccache: true
-    fetches:
-        toolchain:
-            - linux64-clang-5.0
-            - linux64-gcc-7
-            - linux64-rust-1.43
-            - linux64-cbindgen
-            - linux64-sccache
-            - linux64-nasm-2.14.02
-            - linux64-node
-
-linux64-base-toolchains/debug:
-    description: "Linux64 base toolchains Debug"
-    index:
-        product: firefox
-        job-name: linux64-base-toolchains-debug
-    treeherder:
-        platform: linux64/debug
-        symbol: Bb
-    optimization:
-        push-interval-10: null
-    worker-type: b-linux
-    worker:
-        docker-image: {in-tree: debian8-amd64-build-base}
-        max-run-time: 7200
-        env:
-            MOZ_LOW_PARALLELISM_BUILD: '1'
-            PERFHERDER_EXTRA_OPTIONS: base-toolchains
-            FORCE_GCC: '1'
-    run:
-        using: mozharness
-        actions: [get-secrets, build]
-        config:
-            - builds/releng_base_firefox.py
-            - builds/releng_base_linux_64_builds.py
-        script: "mozharness/scripts/fx_desktop_build.py"
-        secrets: true
-        custom-build-variant-cfg: debug
-        mozconfig-variant: debug
-        tooltool-downloads: public
-        need-xvfb: true
-    use-sccache: true
-    fetches:
-        toolchain:
-            - linux64-clang-5.0
-            - linux64-gcc-7
-            - linux64-rust-1.43
-            - linux64-cbindgen
-            - linux64-sccache
-            - linux64-nasm-2.14.02
-            - linux64-node
-            # `fix-stacks` is needed because xpcshell self tests run as part of
-            # the build step. Once bug 1614626 moves them to the xpcshell task,
-            # this dependency can be removed.
-            - linux64-fix-stacks
-
-linux64-base-toolchains-clang/opt:
-    description: "Linux64 base toolchains clang Opt"
-    index:
-        product: firefox
-        job-name: linux64-base-toolchains-clang-opt
-    treeherder:
-        platform: linux64/opt
-        symbol: Bbc
-    run-on-projects: ['mozilla-central']
-    worker-type: b-linux
-    worker:
-        docker-image: {in-tree: debian8-amd64-build-base}
-        max-run-time: 7200
-        env:
-            PERFHERDER_EXTRA_OPTIONS: base-toolchains-clang
-            DISABLE_CLANG_PLUGIN: '1'
-    run:
-        using: mozharness
-        actions: [get-secrets, build]
-        config:
-            - builds/releng_base_firefox.py
-            - builds/releng_base_linux_64_builds.py
-        script: "mozharness/scripts/fx_desktop_build.py"
-        secrets: true
-        tooltool-downloads: public
-        need-xvfb: true
-    fetches:
-        toolchain:
-            - linux64-binutils
-            - linux64-clang-5.0
-            - linux64-rust-1.43
-            - linux64-cbindgen
-            - linux64-nasm-2.14.02
-            - linux64-node
-
-linux64-base-toolchains-clang/debug:
-    description: "Linux64 base toolchains clang Debug"
-    index:
-        product: firefox
-        job-name: linux64-base-toolchains-clang-debug
-    treeherder:
-        platform: linux64/debug
-        symbol: Bbc
-    optimization:
-        push-interval-10: null
-    worker-type: b-linux
-    worker:
-        docker-image: {in-tree: debian8-amd64-build-base}
-        max-run-time: 5400
-        env:
-            PERFHERDER_EXTRA_OPTIONS: base-toolchains-clang
-            DISABLE_CLANG_PLUGIN: '1'
-    run:
-        using: mozharness
-        actions: [get-secrets, build]
-        config:
-            - builds/releng_base_firefox.py
-            - builds/releng_base_linux_64_builds.py
-        script: "mozharness/scripts/fx_desktop_build.py"
-        secrets: true
-        custom-build-variant-cfg: debug
-        mozconfig-variant: debug
-        tooltool-downloads: public
-        need-xvfb: true
-    fetches:
-        toolchain:
-            - linux64-binutils
-            - linux64-clang-5.0
-            - linux64-rust-1.43
-            - linux64-cbindgen
-            - linux64-nasm-2.14.02
-            - linux64-node
-            # `fix-stacks` is needed because xpcshell self tests run as part of
-            # the build step. Once bug 1614626 moves them to the xpcshell task,
-            # this dependency can be removed.
-            - linux64-fix-stacks
-
 linux/opt:
     description: "Linux32 Opt"
     index: