Object.seal(obj) and Object.freeze(obj) should return the input obj....

test/mjsunit/object-freeze.js

 // Copyright 2010 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 173 matching lines @@
 assertFalse(Object.isFrozen(obj4));
 
 // Make sure that an object that has only non-writable, but one
 // configurable property, is not classified as frozen.
 var obj5 = {};
 Object.defineProperty(obj5, 'x', {configurable: true, writable: false});
 Object.defineProperty(obj5, 'y', {configurable: false, writable: false});
 Object.preventExtensions(obj5);
 
 assertFalse(Object.isFrozen(obj5));
+
+// Make sure that Object.freeze returns the frozen object.
+var obj6 = {}
+assertTrue(obj6 === Object.freeze(obj6))