[destructuring] Implement basic binding destructuring infrastructure

test/mjsunit/harmony/destructuring.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.
 //
-// MODULE
+// Flags: --harmony-destructuring
 
-var a, b;
-export { a as c };
-export { a, b as c };
+(function TestObjectLiteralPattern() {
+  var { x : x, y : y } = { x : 1, y : 2 };

[arv (Not doing code reviews), 2015/05/08 19:09:49]

Also:

var {z} = {z: 3};

Should work for free since the parser desugars it before it gets to the
destructuring.

[Dmitry Lomov (no reviews), 2015/05/11 11:07:28]

Done.

+  assertEquals(1, x);
+  assertEquals(2, y);
+}());