Bug 1615544 - Re-enable test_videocontrols.html for Fission. r=Gijs

Differential Revision: https://phabricator.services.mozilla.com/D67192

--HG--
extra : moz-landing-system : lando

toolkit/content/tests/widgets/mochitest.ini

@@ -29,7 +29,7 @@ skip-if = (verify && debug)
 [test_ua_widget_unbind.html]
 [test_videocontrols.html]
 tags = fullscreen
-skip-if = toolkit == 'android' || (verify && debug && (os == 'linux')) || (webrender && (os == 'linux')) || fission #TIMED_OUT #Bug 1484210 #Bug 1511256 #Bug 1615544
+skip-if = toolkit == 'android' || (verify && debug && (os == 'linux')) || (webrender && (os == 'linux')) #TIMED_OUT #Bug 1484210 #Bug 1511256
 [test_videocontrols_keyhandler.html]
 skip-if = (toolkit == 'android') || (os == 'linux') #Bug 1366957
 [test_videocontrols_vtt.html]