Bug 746178 - test timeout in events/test_focus_browserui.xul, disalb eoffending tests on OS X for now

accessible/tests/mochitest/events/test_focus_browserui.xul

@@ -96,6 +96,7 @@
       // back one page in history, moves moves on input of tab document
       gQueue.push(new goBack());
 
+if (!MAC) {
       // open new tab, focus moves to urlbar
       gQueue.push(new synthKey(tabDocument, "t", { ctrlKey: true, window: browserWindow() },
                                new focusChecker(urlbarInput)));
@@ -103,6 +104,9 @@
       // close open tab, focus goes on input of tab document
       gQueue.push(new synthKey(tabDocument, "w", { ctrlKey: true, window: browserWindow() },
                                new focusChecker(inputInDocument)));
+} else {
+      todo(false, "Reenable on Mac after fixing bug 746178!");
+}
 
       gQueue.onFinish = function()
       {