Remove display() from more layout tests

LayoutTests/fast/layers/inline-dirty-z-order-lists.html

 <p>
     Test for <i><a href="https://bugs.webkit.org/show_bug.cgi?id=23848">https://bugs.webkit.org/show_bug.cgi?id=23848</a> REGRESSION: Crash when mouse cursor moves over a link on www.opportuno.de</i>.
 </p>
 <p>
     This tests that changing the z-index of an inline correctly invalidates its
     layer&rsquo;s and its stacking context&rsquo;s z-index lists.
 </p>
 <span id="outer" style="position: relative; z-index: 100;">
     <div id="inner" style="position: absolute; height: 50px; width: 50px; background-color: blue;">
     </div>
 </span>
+<script src="../../resources/run-after-display.js"></script>
 <script>
-    function test()
-    {
+    if (window.testRunner)
+        testRunner.waitUntilDone();
+    runAfterDisplay(function() {
         document.getElementById("outer").style.removeProperty("z-index");
         document.getElementById("inner").style.display = "none";
-    }
-
-    if (window.testRunner) {
-        document.body.offsetTop;
-        testRunner.display();
-        test();
-    } else
-        setTimeout(test, 0);
+        if (window.testRunner)
+            testRunner.notifyDone();
+    });
 </script>