Merge r8390 from bleeding edge (fix missing write barrier in arguments IC).

test/mjsunit/regress/regress-arguments-gc.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 17 matching lines @@
 // Flags: --expose-gc --nocleanup_code_caches_at_gc
 
 function f(x) {
   gc();
   arguments[0] = {};
 }
 
 f(1);
 f(1);
 f(1);