Bug 1765783 - Disable test_videocontrols_focus.html on linux debug for frequent failures. r=aryx,intermittent-reviewers,ahal

Differential Revision: https://phabricator.services.mozilla.com/D191926

toolkit/content/tests/widgets/chrome.toml

@@ -56,6 +56,8 @@ support-files = [
   "head.js",
   "video.ogg",
 ]
-skip-if = ["toolkit == 'android'"]
-
+skip-if = [
+  "toolkit == 'android'",
+  "os == 'linux' && debug", # Bug 1765783
+]
 ["test_videocontrols_onclickplay.html"]