Update most LayoutTests to be agnostic to scrollTopLeftInterop mode

LayoutTests/fast/events/scroll-after-click-on-tab-index.html

Index: LayoutTests/fast/events/scroll-after-click-on-tab-index.html
diff --git a/LayoutTests/fast/events/scroll-after-click-on-tab-index.html b/LayoutTests/fast/events/scroll-after-click-on-tab-index.html
index 2ba7219fc3a1412ee69586de2525ba5cad0d2a71..78058fe3d799e148bc467596fdd6fbc0d22e6d79 100644
--- a/LayoutTests/fast/events/scroll-after-click-on-tab-index.html
+++ b/LayoutTests/fast/events/scroll-after-click-on-tab-index.html
@@ -17,7 +17,7 @@ function runTest()
   testRunner.waitUntilDone();
   testRunner.dumpAsText();
 
-  alert("Scroll position " + document.body.scrollTop);
+  alert("Scroll position " + document.scrollingElement.scrollTop);
   center = getCenterFor(document.getElementById("sp"));
   eventSender.mouseMoveTo(center.x, center.y);
   eventSender.mouseDown();
@@ -29,7 +29,7 @@ function runTest()
 function verifyScrolling()
 {
   debug("Scroll position is more than 0");
-  shouldBe("document.body.scrollTop > 0", "true");
+  shouldBe("document.scrollingElement.scrollTop > 0", "true");
   testRunner.notifyDone();
 }