Bug 1342966 - Enable webgl mochitests for linux64-qr on graphics and m-c. r=dustin

MozReview-Commit-ID: HuayYeHImQC

taskcluster/ci/test/test-sets.yml

@@ -79,6 +79,7 @@ qr-tests:
     - jsreftest
     - mochitest-a11y
     - mochitest-gpu
+    - mochitest-webgl
     - reftest
     - reftest-no-accel
     - xpcshell

taskcluster/ci/test/tests.yml

@@ -801,6 +801,10 @@ mochitest-webgl:
     suite: mochitest/mochitest-gl
     treeherder-symbol: tc-M(gl)
     docker-image: {"in-tree": "desktop1604-test"}
+    run-on-projects:
+        by-test-platform:
+            linux64-qr/.*: ['graphics', 'mozilla-central']
+            default: ['all']
     chunks:
         by-test-platform:
             android.*: 10