Change the check for builtin functions to not be based on identity,...

src/objects-inl.h

Index: src/objects-inl.h
===================================================================
--- src/objects-inl.h	(revision 2572)
+++ src/objects-inl.h	(working copy)
@@ -2341,6 +2341,11 @@
 }
 
 
+bool JSFunction::IsBuiltin() {
+  return context()->global()->IsJSBuiltinsObject();
+}
+
+
 bool JSObject::IsLoaded() {
   return !map()->needs_loading();
 }