Bug 628890 - mochitests-2: test_bug509055.html should not call SimpleTest.finish() before it actually has; (Av1) Wrap the call in SimpleTest.executeSoon() (ftb).

r=Olli.Pettay a=(test-only).

docshell/test/test_bug509055.html

@@ -83,7 +83,7 @@ function runTest() {
 
   popup.close();
 
-  SimpleTest.finish();
+  SimpleTest.executeSoon(SimpleTest.finish);
   dump('Final yield.\n');
   yield;
 }