Bug 1217585 - Enable browser_bug902350.js mochitest in e10s. r=mrbkap

dom/base/test/browser.ini

@@ -15,7 +15,6 @@ support-files =
 skip-if = e10s # Bug ?????? - test directly touches content (contentWindow.iframe.addEventListener)
 [browser_bug902350.js]
 tags = mcb
-skip-if = e10s # Bug ?????? - test e10s utils don't support load events from iframe etc, which this test relies on.
 [browser_messagemanager_loadprocessscript.js]
 [browser_messagemanager_targetframeloader.js]
 [browser_pagehide_on_tab_close.js]