Update most LayoutTests to be agnostic to scrollTopLeftInterop mode

LayoutTests/fast/forms/resources/common.js

 function $(id) {
     return document.getElementById(id);
 }
 
 function createFormControlDataSet() {
     // A list of labelable elements resides in http://www.whatwg.org/specs/web-apps/current-work/multipage/forms.html#category-label
     var formControlClassNames = [
         'HTMLButtonElement',
         'HTMLDataListElement',
         'HTMLFieldSetElement',
@@ skipping 70 matching lines @@
             tagName: 'input',
       };
     }
     formControlDataSet.hiddenType.isLabelable = false;
 
     return formControlDataSet;
 }
 
 function getAbsoluteRect(element) {
     var rect = element.getBoundingClientRect();
-    rect.top += document.body.scrollTop;
-    rect.bottom += document.body.scrollTop;
-    rect.left += document.body.scrollLeft;
-    rect.right += document.body.scrollLeft;
+    rect.top += document.scrollingElement.scrollTop;
+    rect.bottom += document.scrollingElement.scrollTop;
+    rect.left += document.scrollingElement.scrollLeft;
+    rect.right += document.scrollingElement.scrollLeft;
     return rect;
 }
 
 function searchCancelButtonPosition(element) {
     var pos = {};
     pos.x = element.offsetLeft + element.offsetWidth - 9;
     pos.y = element.offsetTop + element.offsetHeight / 2;
     return pos;
 }
 
@@ skipping 103 matching lines @@
     document.addEventListener('focusin', function() {
         if (internals.hasAutofocusRequest(document))
             return;
         if (autofocused)
             return;
         autofocused = true;
         if (loaded)
             callback();
     }, false);
 }