Refactor of various layout tests to use RAF

LayoutTests/svg/custom/js-late-mask-and-object-creation.svg

Index: LayoutTests/svg/custom/js-late-mask-and-object-creation.svg
diff --git a/LayoutTests/svg/custom/js-late-mask-and-object-creation.svg b/LayoutTests/svg/custom/js-late-mask-and-object-creation.svg
index 86a91c79ffe360b67d8c61d88366fcc271a7e849..a8a8ea9d4c021746c2f35fd997f126c825fa822c 100644
--- a/LayoutTests/svg/custom/js-late-mask-and-object-creation.svg
+++ b/LayoutTests/svg/custom/js-late-mask-and-object-creation.svg
@@ -10,7 +10,7 @@
     var content = document.getElementById("content");
 
     function repaintTest() {
-        setTimeout(createObject, 0);
+        requestAnimationFrame(createObject);
     }
 
     function createObject()
@@ -23,7 +23,7 @@
         rect.setAttribute("mask", "url(#dynMask)");
 
         content.appendChild(rect);
-        setTimeout(createMask, 0);
+        requestAnimationFrame(createMask);
     }
 
     function createMask()