Disable gstreamer-in-gstreamer on windows CI

etc/taskcluster/decision_task.py

@@ -490,7 +490,9 @@ def windows_unit(cached=True):
             "mach smoketest --angle",
             "mach package --dev",
             "mach build --dev --libsimpleservo",
-            "mach build --dev -p servo-gst-plugin",
+            # We're getting link errors on windows, due to the x11 feature being
+            # enabled on gstreamer-gl. https://github.com/servo/media/pull/304/
+            "mach build --dev --media-stack=dummy -p servo-gst-plugin",
 
         )
         .with_artifacts("repo/target/debug/msi/Servo.exe",