Update Array Iterator to use numeric indexes

src/array-iterator.js

Index: src/array-iterator.js
diff --git a/src/array-iterator.js b/src/array-iterator.js
index 8f1ab47b8a2088fd72956be2e3fc8bae00ceeac4..defd7342ab2d4fb62cace6a0bb0e4aecbc457684 100644
--- a/src/array-iterator.js
+++ b/src/array-iterator.js
@@ -77,16 +77,15 @@ function ArrayIteratorNext() {
     return CreateIteratorResultObject(void 0, true);
   }
 
-  var elementKey = ToString(index);
   iterator[arrayIteratorNextIndexSymbol] = index + 1;
 
   if (itemKind == ARRAY_ITERATOR_KIND_VALUES)
-    return CreateIteratorResultObject(array[elementKey], false);
+    return CreateIteratorResultObject(array[index], false);
 
   if (itemKind == ARRAY_ITERATOR_KIND_ENTRIES)
-    return CreateIteratorResultObject([elementKey, array[elementKey]], false);
+    return CreateIteratorResultObject([index, array[index]], false);
 
-  return CreateIteratorResultObject(elementKey, false);
+  return CreateIteratorResultObject(index, false);
 }
 
 function ArrayEntries() {