Check holder before optimizing calls to global functions....

test/mjsunit/regress/regress-1106.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 22 matching lines @@
 x.foo = 3;
 x.bar = 4;
 delete x.foo;
 x.foo = 5;
 
 function f() { return foo; }
 
 for (i=0 ; i < 100000; ++i) {
   assertEquals(5, f());
 }
+
+// Test calls on functions defined in the prototype of the global object.
+x.gee = function() { return 42; }
+function g() { return gee(); }
+
+for (i=0 ; i < 100000; ++i) {
+  assertEquals(42, g());
+}