Bug 1503636 - Enable mochitest-media on android-hw-p2 for built-projects, r=jmaher.

taskcluster/ci/test/mochitest.yml

@@ -277,10 +277,7 @@ mochitest-media:
             windows10-64-ccov/debug: 7200
             macosx64-ccov/debug: 7200
             default: 5400
-    run-on-projects:
+    run-on-projects: built-projects
-        by-test-platform:
-            android-hw.*: ['try']
-            default: built-projects
     loopback-video: true
     virtualization:
         by-test-platform: