Unprefix usage of -webkit-transform in tests

LayoutTests/css3/filters/effect-all-on-background-hw.html

 <script>
   if (window.testRunner)
     window.testRunner.dumpAsTextWithPixelResults();
 </script>
 <svg xmlns="http://www.w3.org/2000/svg" width="0" height="0" version="1.1">
   <defs>
     <filter id="xor" color-interpolation-filters="sRGB">
       <feColorMatrix type="matrix" values="1 0 0 0 0  0 1 0 0 0  0 0 1 0 0  0 0 0 0.5 0" result="transp"/>
       <feOffset dx="10" dy="10"/>
       <feComposite in2="transp" operator="xor"/>
     </filter>
   </defs>
 </svg>
 <style>
 li {
     margin: 10px;
     width: 160px;
     height: 90px;
     background-image: url(resources/reference.png);
     display: block;
     float: left;
-    -webkit-transform:translateZ(0);
+    transform:translateZ(0);
 }
 </style>
 <ul>
 <li style="-webkit-filter: blur(3px)"/>
 <li style="-webkit-filter: brightness(0.5)"/>
 <li style="-webkit-filter: contrast(3)"/>
 <li style="-webkit-filter: drop-shadow(5px 5px 5px blue)"/>
 <li style="-webkit-filter: grayscale(0.5)"/>
 <li style="-webkit-filter: hue-rotate(180deg)"/>
 <li style="-webkit-filter: invert(1.0)"/>
 <li style="-webkit-filter: opacity(0.5)"/>
 <li style="-webkit-filter: saturate(10)"/>
 <li style="-webkit-filter: sepia(1.0)"/>
 <li style="-webkit-filter: url(#xor)"/>
 </ul>