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

test/mjsunit/array-length.js

 // Copyright 2008 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 84 matching lines @@
 assertEquals(Math.pow(2,30)+1, a.length);
 
 assertEquals(0, a[0]);
 assertEquals(1000, a[1000]);
 assertEquals(Math.pow(2,30)-1, a[Math.pow(2,30)-1]);
 assertEquals('undefined', typeof a[Math.pow(2,31)-1]);
 assertEquals('undefined', typeof a[Math.pow(2,32)-2], "top");
 
 
 var a = new Array();
-assertEquals(12, a.length = new Number(12));
+assertEquals(Object(12), a.length = new Number(12));
 assertEquals(12, a.length);
 
 
 var o = { length: -23 };
 Array.prototype.pop.apply(o);
 assertEquals(4294967272, o.length);
 
 // Check case of compiled stubs.
 var a = [];
 for (var i = 0; i < 7; i++) {
   assertEquals(3, a.length = 3);
 
   var t = 239;
   t = a.length = 7;
   assertEquals(7, t);
 }