Begins work on ARM64, first assembler test.

runtime/vm/runtime_entry_test.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// TODO(zra): Remove when tests are ready to enable.
+#include "platform/globals.h"
+#if !defined(TARGET_ARCH_ARM64)
+
 #include "vm/runtime_entry.h"
 
 #include "vm/object.h"
 #include "vm/symbols.h"
 #include "vm/verifier.h"
 
 namespace dart {
 
 // Add function to a class and that class to the class dictionary so that
 // frame walking can be used.
@@ skipping 37 matching lines @@
                           RawObject* arg0, RawObject* arg1) {
   // Ignoring overflow in the calculation below and using the internal
   // representation of Smi directly without using any handlized code.
   intptr_t result = reinterpret_cast<intptr_t>(arg0) +
       reinterpret_cast<intptr_t>(arg1);
   return reinterpret_cast<RawObject*>(result);
 }
 END_LEAF_RUNTIME_ENTRY
 
 }  // namespace dart
+
+#endif  // !defined(TARGET_ARCH_ARM64)