Merge arguments branch to bleeding merge.

test/mjsunit/arguments.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 134 matching lines @@
 }
 f5(2, 3, 5);
 
 
 function f6(x, y) {
   x = "x";
   arguments[1] = "y";
   return [arguments.length, arguments[0], y, arguments[2]];
 }
 
-assertArrayEquals([0, "x", "y", void 0], f6());
-assertArrayEquals([1, "x", "y", void 0], f6(1));
+assertArrayEquals([0, void 0, void 0, void 0], f6());
+assertArrayEquals([1, "x", void 0, void 0], f6(1));
 assertArrayEquals([2, "x", "y", void 0], f6(9, 17));
 assertArrayEquals([3, "x", "y", 7], f6(3, 5, 7));
 assertArrayEquals([4, "x", "y", "c"], f6("a", "b", "c", "d"));
 
 
 function list_args(a) {
   assertEquals("function", typeof a.callee);
   var result = [];
   result.push(a.length);
   for (i = 0; i < a.length; i++) result.push(a[i]);
   return result;
 }
 
 
 function f1(x, y) {
   function g(p) {
     x = p;
   }
   g(y);
   return list_args(arguments);
 }
 
 assertArrayEquals([0], f1());
 assertArrayEquals([1, void 0], f1(3));
 assertArrayEquals([2, 5, 5], f1(3, 5));
 assertArrayEquals([3, 5, 5, 7], f1(3, 5, 7));