Unprefix usage of -webkit-transform in tests

LayoutTests/compositing/gestures/resources/link-highlight-style.css

 /*Used for applying style to a <span> so it looks like a highlight*/
 .fauxHighlight {
   background-color: rgb(0, 255, 0);
   color: rgb(0, 255, 0);
 }
 
 .fauxHighlightSquare {
   background-color: rgb(0, 255, 0);
   color: rgb(0, 255, 0);
 }
@@ skipping 38 matching lines @@
   background-color: rgb(0, 255, 0);
   z-index: 1;
   position: absolute;
 }
 
 .squaredHighlight {
   -webkit-border-radius: 0px;
 }
 
 .composited {
-  -webkit-transform: translateZ(0);
+  transform: translateZ(0);
 }