Fix some corner cases in skipping native methods using caller.

src/accessors.cc

Index: src/accessors.cc
===================================================================
--- src/accessors.cc	(revision 12398)
+++ src/accessors.cc	(working copy)
@@ -755,6 +755,9 @@
     caller = potential_caller;
     potential_caller = it.next();
   }
+  if (!caller->shared()->native()) {
+    caller = potential_caller;
+  }
   // If caller is bound, return null. This is compatible with JSC, and
   // allows us to make bound functions use the strict function map
   // and its associated throwing caller and arguments.