Fix map space explosion from changing the arguments and caller properties on native functions.

src/accessors.cc

Index: src/accessors.cc
===================================================================
--- src/accessors.cc	(revision 9124)
+++ src/accessors.cc	(working copy)
@@ -599,6 +599,7 @@
   if (!found_it) return isolate->heap()->undefined_value();
   Handle<JSFunction> function(holder, isolate);
 
+  if (function->shared()->native()) return isolate->heap()->null_value();
   // Find the top invocation of the function by traversing frames.
   List<JSFunction*> functions(2);
   for (JavaScriptFrameIterator it(isolate); !it.done(); it.Advance()) {
@@ -732,6 +733,7 @@
   bool found_it = false;
   JSFunction* holder = FindInPrototypeChain<JSFunction>(object, &found_it);
   if (!found_it) return isolate->heap()->undefined_value();
+  if (holder->shared()->native()) return isolate->heap()->null_value();
   Handle<JSFunction> function(holder, isolate);
 
   FrameFunctionIterator it(isolate, no_alloc);