Avoid converting key to string for deleting of elements

src/array.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var $arrayConcat;
 var $arrayPush;
 var $arrayPop;
 var $arrayShift;
 var $arraySlice;
 var $arraySplice;
@@ skipping 460 matching lines @@
   if (n == 0) {
     array.length = n;
     return;
   }
 
   if (%IsObserved(array))
     return ObservedArrayPop.call(array, n);
 
   n--;
   var value = array[n];
-  Delete(array, $toName(n), true);
+  Delete(array, n, true);
   array.length = n;
   return value;
 }
 
 
 function ObservedArrayPush() {
   var n = TO_UINT32(this.length);
   var m = %_ArgumentsLength();
 
   try {
@@ skipping 1204 matching lines @@
 
 $arrayConcat = ArrayConcatJS;
 $arrayPush = ArrayPush;
 $arrayPop = ArrayPop;
 $arrayShift = ArrayShift;
 $arraySlice = ArraySlice;
 $arraySplice = ArraySplice;
 $arrayUnshift = ArrayUnshift;
 
 });