Implement ES6 Array.prototype.toString behind --harmony-tostring

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.
 
 "use strict";
 
 // This file relies on the fact that the following declarations have been made
 // in runtime.js:
 // var $Array = global.Array;
 
@@ skipping 343 matching lines @@
     func = this.join;
     if (func === ArrayJoin) {
       return Join(this, this.length, ',', ConvertToString);
     }
     array = this;
   } else {
     array = ToObject(this);
     func = array.join;
   }
   if (!IS_SPEC_FUNCTION(func)) {
-    return %_CallFunction(array, NoSideEffectsObjectToString);
+    return %_CallFunction(array, DefaultObjectToString);
   }
   return %_CallFunction(array, func);
 }
 
 
 function ArrayToLocaleString() {
   var array = ToObject(this);
   var arrayLen = array.length;
   var len = TO_UINT32(arrayLen);
   if (len === 0) return "";
@@ skipping 1206 matching lines @@
   ));
 
   SetUpLockedPrototype(InternalPackedArray, $Array(), $Array(
     "join", getFunction("join", ArrayJoin),
     "pop", getFunction("pop", ArrayPop),
     "push", getFunction("push", ArrayPush)
   ));
 }
 
 SetUpArray();