Bug 1437295 - Remove unnecessary change from bug 1374166. r=botond

The change that was made in bug 1374166 was attempting to fix the
problem fixed by the previous patch, but didn't actually succeed (it
just made it less likely to occur). Now that we have the proper fix we
can revert that botched attempt to speed up the test a little bit.

MozReview-Commit-ID: 3hWZ6bFTdxb

--HG--
extra : rebase_source : 15a8c6e183a5d7a09527ac3857b0eefb563c5165

gfx/layers/apz/test/mochitest/test_bug1151663.html

@@ -8,7 +8,6 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1151663
   <title>Test for Bug 1151663</title>
   <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
   <script type="application/javascript" src="apz_test_utils.js"></script>
-  <script type="application/javascript" src="/tests/SimpleTest/paint_listener.js"></script>
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   <script type="application/javascript">
 
@@ -20,7 +19,6 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=1151663
       // inside an iframe which means we have no control over the root APZC.
       var w = null;
       pushPrefs([["apz.test.logging_enabled", true]])
-          .then(waitUntilApzStable)
           .then(function() {
             w = window.open("helper_bug1151663.html", "_blank");
           });