Use the LookupIterator to transition to elements accessors

test/mjsunit/element-accessor.js

+// Copyright 2015 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 () {
+  var o = [];
+  o.__proto__ = {};
+
+  function store(o, i, v) {
+    o[i] = v;
+  }
+
+  store(o, 0, 0);
+  store(o, 1, 0);
+  store(o, 2, 0);
+  o.__proto__[10000000] = 1;
+
+  var set = 0;
+
+  Object.defineProperty(o, "3", {
+    get:function() { return 100; },
+    set:function(v) { set = v; }});
+
+  store(o, 3, 1000);
+  assertEquals(1000, set);
+  assertEquals(100, o[3]);
+})();
+
+(function () {
+  var o = new Int32Array();
+  Object.defineProperty(o, "0", {get: function(){}});
+  assertEquals(undefined, Object.getOwnPropertyDescriptor(o, "0"));
+})();