Bug 1389983 - Disable...

Bug 1389983 - Disable dom/media/tests/mochitest/test_getUserMedia_addtrack_removetrack_events.html on linux debug for frequent failures. r=me, a=test-only

dom/media/tests/mochitest/mochitest.ini

@@ -49,6 +49,7 @@ skip-if = toolkit == 'android' # android(Bug 1189784, timeouts on 4.3 emulator),
 [test_getUserMedia_addTrackRemoveTrack.html]
 skip-if = android_version == '18' || os == 'linux' # android(Bug 1189784, timeouts on 4.3 emulator), linux bug 1377450
 [test_getUserMedia_addtrack_removetrack_events.html]
+skip-if os == 'linux' && debug # Bug 1389983
 [test_getUserMedia_basicAudio.html]
 [test_getUserMedia_basicVideo.html]
 [test_getUserMedia_basicVideo_playAfterLoadedmetadata.html]