perf(get-element-stack): improve getElementStack performance on large…

… pages (#4026)

* perf(get-element-stack): improve getElementStack performance on large pages

* use memoize instead of cache in getScroll

lib/core/utils/get-scroll.js

@@ -1,12 +1,14 @@
+import memoize from './memoize';
+
 /**
  * Get the scroll position of given element
  * @method getScroll
  * @memberof axe.utils
- * @param {Element} node
+ * @param {Element} elm
  * @param {buffer} (Optional) allowed negligence in overflow
  * @returns {Object | undefined}
  */
-export default function getScroll(elm, buffer = 0) {
+function getScroll(elm, buffer = 0) {
   const overflowX = elm.scrollWidth > elm.clientWidth + buffer;
   const overflowY = elm.scrollHeight > elm.clientHeight + buffer;
 
@@ -38,3 +40,5 @@ function isScrollable(style, prop) {
   const overflowProp = style.getPropertyValue(prop);
   return ['scroll', 'auto'].includes(overflowProp);
 }
+
+export default memoize(getScroll);