Bug 1707791 - Remove unneeded clang-9 references. r=rjl

Differential Revision: https://phabricator.services.mozilla.com/D113454

Depends on D113453

--HG--
extra : amend_source : a813e7ed1b1667c6e393aaf7ae285d2c6882713c

taskcluster/ci/toolchain/kind.yml

@@ -14,13 +14,11 @@ reference-jobs:
     - linux64-aarch64-sysroot
     - linux64-binutils
     - linux64-cbindgen
-    - linux64-cctools-port-clang-9
     - linux64-cctools-port-clang-11
     - linux64-cctools-port-clang-12
     - linux64-cctools-port
     - linux64-clang
     - linux64-clang-7
-    - linux64-clang-9
     - linux64-clang-11
     - linux64-clang-12
     - linux64-clang-aarch64-cross
@@ -60,14 +58,12 @@ reference-jobs:
     - linux64-wine
     - macosx64-aarch64-compiler-rt-12
     - macosx64-x64-compiler-rt-12
-    - macosx64-clang-9
     - macosx64-clang-12
     - macosx64-fix-stacks
     - macosx64-minidump-stackwalk
     - macosx64-node
     - mingw32-rust-1.47
     - wasi-sysroot
-    - wasi-sysroot-9
     - wasi-sysroot-11
     - wasi-sysroot-12
     - win32-fix-stacks