Bug 1426118 - Turn on webgl mochitests for windows10-64 QuantumRender builds. r=dustin

The webgl mochitests will run on all nightly branches (so inbound, autoland,
m-c, try) by default.

MozReview-Commit-ID: E3KPTbbxE3E

--HG--
extra : rebase_source : 4001221ba39b5b7f00dc70c8cd2b1e3a18599cd7

taskcluster/ci/test/mochitest.yml

@@ -364,6 +364,7 @@ mochitest-webgl:
     run-on-projects:
         by-test-platform:
             windows10-64-ccov/.*: []  # Do not run on Windows ccov, see bug 1419475.
+            .*-qr/.*: ['mozilla-central', 'autoland', 'mozilla-inbound', 'try']  # exclude beta and project branches
             default: built-projects
     virtualization: virtual-with-gpu
     chunks:

taskcluster/ci/test/test-sets.yml

@@ -158,6 +158,7 @@ windows-qr-tests:
     - crashtest
     - mochitest-gpu
     - mochitest-media
+    - mochitest-webgl
 
 windows-qr-talos:
     - talos-chrome