Forward onscroll on body and frameset to window

LayoutTests/fast/dom/Window/script-tests/HTMLFrameSetElement-window-eventListener-attributes.js

 description("This tests that setting window event listeners on the frameset, sets them on the window.");
 
 function gc()
 {
     if (window.GCController)
         return GCController.collect();
 
     for (var i = 0; i < 10000; i++) { // > force garbage collection (FF requires about 9K allocations before a collect)
         var s = new String("");
     }
@@ skipping 35 matching lines @@
 shouldBe("window.onoffline", "frameSet.onoffline");
 
 frameSet.ononline = func;
 shouldBe("window.ononline", "func");
 shouldBe("window.ononline", "frameSet.ononline");
 
 frameSet.onresize = func;
 shouldBe("window.onresize", "func");
 shouldBe("window.onresize", "frameSet.onresize");
 
+frameSet.onscroll = func;
+shouldBe("window.onscroll", "func");
+shouldBe("window.onscroll", "frameSet.onscroll");
+
 frameSet.onstorage = func;
 shouldBe("window.onstorage", "func");
 shouldBe("window.onstorage", "frameSet.onstorage");
 
 frameSet.onunload = func;
 shouldBe("window.onunload", "func");
 shouldBe("window.onunload", "frameSet.onunload");
 window.onunload = null;
 
 gc();