Make global NaN, Infinity and undefined read only.

test/mjsunit/undeletable-functions.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 171 matching lines @@
 
 
 function CheckReadOnlyAttr(type, prop) {
   var old = type[prop];
   if (!type[prop]) return;
   assertTrue(type.hasOwnProperty(prop), "inherited: " + prop);
   var deleted = delete type[prop];
   assertFalse(deleted, "delete operator returned true: " + prop);
   assertTrue(type.hasOwnProperty(prop), "not there after delete: " + prop);
   type[prop] = "foo";
-  assertEquals("foo", type[prop], "overwritable: " + prop);
+  assertEquals(old, type[prop], "not overwritable: " + prop);
 }
 
 print("OK");