Update most LayoutTests to be agnostic to scrollTopLeftInterop mode

LayoutTests/fast/scroll-behavior/main-frame-element-scrollTo.html

Index: LayoutTests/fast/scroll-behavior/main-frame-element-scrollTo.html
diff --git a/LayoutTests/fast/scroll-behavior/main-frame-element-scrollTo.html b/LayoutTests/fast/scroll-behavior/main-frame-element-scrollTo.html
index fc44418223c1ed710960e80ec247d332901c9fb5..104d890748cbd136debcdcc53e4544038da10897 100644
--- a/LayoutTests/fast/scroll-behavior/main-frame-element-scrollTo.html
+++ b/LayoutTests/fast/scroll-behavior/main-frame-element-scrollTo.html
@@ -34,9 +34,9 @@
           scrollToOptions.left = testCase.x;
         if (testCase.y)
           scrollToOptions.top = testCase.y;
-        document.body.scrollTo(scrollToOptions);
+        document.scrollingElement.scrollTo(scrollToOptions);
       } else {
-        document.body.scrollTo(testCase.x, testCase.y);
+        document.scrollingElement.scrollTo(testCase.x, testCase.y);
       }
     }
 
@@ -67,7 +67,7 @@
         testCases.push(new ScrollBehaviorTestCase(testScrolls[i]));
       }
 
-      var scrollBehaviorTest = new ScrollBehaviorTest(document.body,
+      var scrollBehaviorTest = new ScrollBehaviorTest(document.scrollingElement,
                                                       document,
                                                       testCases,
                                                       getEndPosition,