Bug 1384724 - Use matching virtualization for Stylo tests. r=catlee

We need to use the same virtualization setting as the regular tests that these
Stylo tests were copied from to ensure we get the right machine type for
Windows runs.

MozReview-Commit-ID: GUetZ2IheZY

--HG--
extra : rebase_source : 48d318b340c24b46b759026539929a69ecbec8f2

taskcluster/ci/test/tests.yml

@@ -1246,6 +1246,7 @@ reftest-stylo:
     description: "Reftest run for Stylo"
     suite: reftest/reftest-stylo
     treeherder-symbol: tc-R(Rs)
+    virtualization: virtual-with-gpu
     docker-image: {"in-tree": "desktop1604-test"}
     chunks: 16
     run-on-projects: