Unprefix usage of -webkit-transform in tests

LayoutTests/fast/transforms/shadows.html

 <style>
     body { margin: 0; color: lightgreen; font-family: Ahem; font-size: 20px; }
 
     .square {
         width: 30px;
         height: 30px;
         background-color: lightyellow;
         margin: 20px;
         float: left;
         padding: 5px;
     }
 
     .rounded {
         -webkit-border-radius: 10px;
     }
 
     .transform1 {
-        -webkit-transform: rotate(45deg);
+        transform: rotate(45deg);
     }
 
     .transform2 {
-        -webkit-transform: scale(0.5, 1);
+        transform: scale(0.5, 1);
     }
 
     .transform3 {
-        -webkit-transform: rotate(45deg) scale(0.5, 1);
+        transform: rotate(45deg) scale(0.5, 1);
     }
 
     .transform4 {
-        -webkit-transform: skewX(45deg);
+        transform: skewX(45deg);
     }
 
     .shadow1 {
         -webkit-box-shadow: black 10px 10px 0;
     }
 
     .shadow2 {
         -webkit-box-shadow: black 10px 10px 10px;
     }
 
@@ skipping 42 matching lines @@
 <div class="square text-shadow2 transform1">X</div>
 <div class="square text-shadow2 transform2">X</div>
 <div class="square text-shadow2 transform3">X</div>
 <div class="square text-shadow2 transform4">X</div>
 <div style="clear: both;"></div>
 <div class="square text-shadow3">X</div>
 <div class="square text-shadow3 transform1">X</div>
 <div class="square text-shadow3 transform2">X</div>
 <div class="square text-shadow3 transform3">X</div>
 <div class="square text-shadow3 transform4">X</div>