Cleanup of mjsunit.js code and make assertEquals more strict.

test/mjsunit/arguments-apply.js

 // Copyright 2009 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 55 matching lines @@
 
 assertEquals(2, ShadowArguments().length);
 assertEquals(3, ShadowArguments()[0]);
 assertEquals(4, ShadowArguments()[1]);
 
 
 function NonObjectReceiver(receiver) {
   return ReturnReceiver.apply(receiver, arguments);
 }
 
-assertEquals(42, NonObjectReceiver(42));
+assertEquals(Object(42), NonObjectReceiver(42));
 assertEquals("object", typeof NonObjectReceiver(42));
-assertTrue(NonObjectReceiver(42) instanceof Number);
-assertTrue(this === NonObjectReceiver(null));
-assertTrue(this === NonObjectReceiver(void 0));
+assertInstanceof(NonObjectReceiver(42), Number);
+assertSame(this, NonObjectReceiver(null));
+assertSame(this, NonObjectReceiver(void 0));
 
 
 function FunctionReceiver() {
   return ReturnReceiver.apply(Object, arguments);
 }
 
 assertTrue(Object === FunctionReceiver());
 
 
 function ShadowApply() {
@@ skipping 34 matching lines @@
 
 assertEquals(0, ShadowArgumentsWithConstant().length);
 assertEquals(0, ShadowArgumentsWithConstant(1).length);
 assertEquals(0, ShadowArgumentsWithConstant(1, 2).length);
 
 
 // Make sure we can deal with unfolding lots of arguments on the
 // stack even in the presence of the apply optimizations.
 var array = new Array(2048);
 assertEquals(2048, Global.apply(this, array).length);