Bug 1733631 - [ci] Stop using 'by-variant' in WPT tasks with no variants, r=gbrown

Depends on D129082

Differential Revision: https://phabricator.services.mozilla.com/D129083

taskcluster/ci/test/web-platform.yml

@@ -114,25 +114,9 @@ web-platform-tests-backlog:
             default: 3600
     variants: []
     e10s: true
-    run-on-projects:
-        by-variant:
-            fission:
-                by-test-platform:
-                    linux.*64-qr/debug: ['trunk']
-                    linux.*64(-shippable)?-qr/opt: ['trunk']
-                    windows10-64-2004(-shippable)?-qr/opt: ['trunk']
-                    default: []
-            default: ['mozilla-central']
+    run-on-projects: ['mozilla-central']
     test-manifest-loader: null  # don't load tests in the taskgraph
-    tier:
-        by-variant:
-            fission:
-                by-test-platform:
-                    linux.*64-qr/debug: 1
-                    linux.*64(-shippable)?-qr/opt: 1
-                    windows10-64-2004(-shippable)?-qr/opt: 1
-                    default: 2
-            default: 2
+    tier: 2
     mozharness:
         chunked: true
         extra-options:
@@ -209,25 +193,9 @@ web-platform-tests-reftest-backlog:
     chunks: 1
     variants: []
     e10s: true
-    run-on-projects:
-        by-variant:
-            fission:
-                by-test-platform:
-                    linux.*64-qr/debug: ['trunk']
-                    linux.*64(-shippable)?-qr/opt: ['trunk']
-                    windows10-64-2004(-shippable)?-qr/opt: ['trunk']
-                    default: []
-            default: ['mozilla-central']
+    run-on-projects: ['mozilla-central']
     test-manifest-loader: null  # don't load tests in the taskgraph
-    tier:
-        by-variant:
-            fission:
-                by-test-platform:
-                    linux.*64-qr/debug: 1
-                    linux.*64(-shippable)?-qr/opt: 1
-                    windows10-64-2004(-shippable)?-qr/opt: 1
-                    default: 2
-            default: 2
+    tier: 2
     mozharness:
         extra-options:
             - --test-type=reftest
@@ -459,34 +427,18 @@ test-verify-wpt:
     treeherder-symbol: TVw
     max-run-time: 10800
     run-on-projects:
-        by-variant:
-            fission:
-                by-test-platform:
-                    linux.*64-qr/debug: ['trunk']
-                    linux.*64(-shippable)?-qr/opt: ['trunk']
-                    windows10-64-2004(-shippable)?-qr/opt: ['trunk']
-                    default: []
-            default:
-                by-test-platform:
-                    # do not run on ccov or asan
-                    .*-ccov.*/.*: []
-                    .*-asan.*/.*: []
-                    .*shippable.*: []
-                    # do not run on beta or release: usually just confirms earlier results
-                    default: ['integration']
+        by-test-platform:
+            # do not run on ccov or asan
+            .*-ccov.*/.*: []
+            .*-asan.*/.*: []
+            .*shippable.*: []
+            # do not run on beta or release: usually just confirms earlier results
+            default: ['integration']
     built-projects-only: true
     test-manifest-loader: null  # don't load tests in the taskgraph
     optimization:
         test-verify: ["test-verify-wpt"]
-    tier:
-        by-variant:
-            fission:
-                by-test-platform:
-                    linux.*64-qr/debug: 1
-                    linux.*64(-shippable)?-qr/opt: 1
-                    windows10-64-2004(-shippable)?-qr/opt: 1
-                    default: 2
-            default: 2
+    tier: 2
     mozharness:
         extra-options:
             - --verify