Back out 95d45bb51f96 (bug 1245937) because browser_chatwindow.js still exceeds the timeout threshold

browser/base/content/test/chat/browser.ini

@@ -5,6 +5,7 @@ support-files =
   chat.html
 
 [browser_chatwindow.js]
+skip-if = true # Bug 1245937 - Intermittent failures/timeouts.
 [browser_focus.js]
 [browser_tearoff.js]
 skip-if = true # Bug 1245805 - tearing off chat windows causes a browser crash.