Merge up to 8597 to experimental/gc from the bleeding edge.

test/mjsunit/regress/regress-1491.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 18 matching lines @@
 // receivers.
 
 // Create an object with an array as the prototype.
 var o = Object.create([]);
 
 // Check that writing the length property of the non-array object
 // works as expected.
 var value = "asdf";
 o.length = value;
 assertEquals(value, o.length);