Enable ES6 iteration by default

test/mjsunit/builtins.js

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 23 matching lines @@
 
 var names = Object.getOwnPropertyNames(builtins);
 
 function isFunction(obj) {
   return typeof obj == "function";
 }
 
 function isV8Native(name) {
   return name == "GeneratorFunctionPrototype" ||
       name == "SetIterator" ||
-      name == "MapIterator";
+      name == "MapIterator" ||
+      name == "ArrayIterator" ||
+      name == "StringIterator";
 }
 
 function checkConstructor(func, name) {
   // A constructor is a function with a prototype and properties on the
   // prototype object besides "constructor";
   if (name.charAt(0) == "$") return;
   if (typeof func.prototype != "object") return;
   var propNames = Object.getOwnPropertyNames(func.prototype);
   if (propNames.length == 0 ||
       (propNames.length == 1 && propNames[0] == "constructor")) {
@@ skipping 24 matching lines @@
 
 for (var i = 0; i < names.length; i++) {
   var name = names[i];
   var desc = Object.getOwnPropertyDescriptor(builtins, name);
   assertTrue(desc.hasOwnProperty("value"));
   var value = desc.value;
   if (isFunction(value)) {
     checkConstructor(value, name);
   }
 }