Also return the resulting array in GetSortedArrayKeys

src/js/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.
 
 (function(global, utils, extrasUtils) {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
@@ skipping 70 matching lines @@
   if (IS_NUMBER(indices)) {
     var keys = new InternalArray();
     // It's an interval
     var limit = indices;
     for (var i = 0; i < limit; ++i) {
       var e = array[i];
       if (!IS_UNDEFINED(e) || i in array) {
         keys.push(i);
       }
     }
+    return keys;
   }
   return InnerArraySort(indices, indices.length, KeySortCompare);
 }
 
 
 function SparseJoinWithSeparatorJS(array, keys, length, convert, separator) {
   var keys_length = keys.length;
   var elements = new InternalArray(keys_length * 2);
   for (var i = 0; i < keys_length; i++) {
     var key = keys[i];
@@ skipping 1859 matching lines @@
 %InstallToContext([
   "array_pop", ArrayPop,
   "array_push", ArrayPush,
   "array_shift", ArrayShift,
   "array_splice", ArraySplice,
   "array_slice", ArraySlice,
   "array_unshift", ArrayUnshift,
 ]);
 
 });