Begins work on ARM64, first assembler test.

runtime/vm/heap_test.cc

 // Copyright (c) 2012, 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.
 
+#include "platform/globals.h"
+#if !defined(TARGET_ARCH_ARM64)
+
 #include "platform/assert.h"
 #include "vm/dart_api_impl.h"
 #include "vm/globals.h"
 #include "vm/heap.h"
 #include "vm/unit_test.h"
 
 namespace dart {
 
 TEST_CASE(OldGC) {
   const char* kScriptChars =
@@ skipping 184 matching lines @@
     }
   }
   {
     NoGCScope no_gc;
     FindNothing find_nothing;
     EXPECT(Object::null() == heap->FindObject(&find_nothing));
   }
 }
 
 }  // namespace dart.
+
+#endif  // !defined(TARGET_ARCH_ARM64)