Unprefix usage of -webkit-transform in tests

LayoutTests/fast/dom/Element/getClientRects.html

 <script src="../../../resources/js-test.js"></script>
 <style>
     #base {
         width: 300px;
         height: 100px;
     }
 
     #border {
         border: 10px solid #999;
         width: 300px;
         height: 100px;
     }
 
     #margin {
         margin: 10px;
         width: 300px;
         height: 100px;
     }
 
     #transform {
-        -webkit-transform: translateX(50px) rotate(45deg);
+        transform: translateX(50px) rotate(45deg);
         width: 100px;
         height: 100px;
     }
 
     #columns {
         -webkit-column-count: 3;
         width: 300px;
     }
 
     #inline {
@@ skipping 124 matching lines @@
 
     var tests = document.getElementsByClassName("testBox");
     for (var i = 0; i < tests.length; ++i)
         test(i + 1, tests[i]);
 
     if (window.testRunner) {
         var area = document.getElementById('testArea');
         area.parentNode.removeChild(area);
     }
 </script>