Support for JNI local reference cookie.

This also fixes a cross compilation bug in reseting the top of the
indirect reference table following a down call.

Change-Id: I40d913a6f86dadfe87b58d6d13a1ff3613f270ac
diff --git a/src/thread.h b/src/thread.h
index 123a376..ebab184 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -432,6 +432,7 @@
     native_to_managed_record_ = record;
     top_of_managed_stack_.SetSP(NULL);
   }
+
   void PopNativeToManagedRecord(const NativeToManagedRecord& record) {
     native_to_managed_record_ = record.link_;
     top_of_managed_stack_.SetSP(reinterpret_cast<Method**>(record.last_top_of_managed_stack_));