Begins work on ARM64, first assembler test.

runtime/vm/benchmark_test.cc

Index: runtime/vm/benchmark_test.cc
===================================================================
--- runtime/vm/benchmark_test.cc	(revision 34648)
+++ runtime/vm/benchmark_test.cc	(working copy)
@@ -8,6 +8,7 @@
 #include "bin/file.h"
 
 #include "platform/assert.h"
+#include "platform/globals.h"
 
 #include "vm/dart_api_impl.h"
 #include "vm/stack_frame.h"
@@ -30,6 +31,8 @@
   }
 }
 
+// TODO(zra): Remove when tests are ready to enable.
+#if !defined(TARGET_ARCH_ARM64)
 
 //
 // Measure compile of all functions in dart core lib classes.
@@ -578,4 +581,6 @@
   benchmark->set_score(elapsed_time);
 }
 
+#endif  // !defined(TARGET_ARCH_ARM64)
+
 }  // namespace dart