Bug 1418252 - Allow 'virtualization' key to be keyed by test platform. r=jmaher

--HG--
extra : rebase_source : 978e4705b1082f633301a4462ceb11817f6d1634

taskcluster/taskgraph/transforms/tests.py

@@ -623,6 +623,7 @@ def handle_keyed_by(config, tests):
         'mozharness.requires-signed-builds',
         'mozharness.script',
         'worker-type',
+        'virtualization',
     ]
     for test in tests:
         for field in fields: