Bug 1781539 - disable dom/media/test/test_loop.html in windows media foundation variant. r=alwu

Differential Revision: https://phabricator.services.mozilla.com/D160692

dom/media/test/mochitest_compat.ini

@@ -809,6 +809,8 @@ skip-if = (android_version == '25' && debug) # android(bug 1232305)
 [test_load_source.html]
 [test_load_source_empty_type.html]
 [test_loop.html]
+skip-if =
+  wmfme # Bug 1781539
 [test_looping_eventsOrder.html]
 [test_mediatrack_consuming_mediaresource.html]
 [test_mediatrack_events.html]