Unprefix usage of -webkit-transform in tests

LayoutTests/compositing/flat-with-transformed-child.html

Index: LayoutTests/compositing/flat-with-transformed-child.html
diff --git a/LayoutTests/compositing/flat-with-transformed-child.html b/LayoutTests/compositing/flat-with-transformed-child.html
index bb5665922acb78c7020907dd3ca27f476bc4013a..467da108363ba99e6ab0830d13a8b9ac2abf060d 100644
--- a/LayoutTests/compositing/flat-with-transformed-child.html
+++ b/LayoutTests/compositing/flat-with-transformed-child.html
@@ -14,12 +14,12 @@
       background-color: green;
       opacity: 0.9999;
       -webkit-transform-style: flat;
-      -webkit-transform: rotateY(80deg);
+      transform: rotateY(80deg);
     }
 
     #child {
       background-color: green;
-      -webkit-transform: translateZ(0);
+      transform: translateZ(0);
     }
 
     #bad {