art: Handle x86_64 architecture equal to x86

This patch forces FE/ME to treat x86_64 as x86 exactly.
The x86_64 logic will be revised later when assembly will be ready.

Change-Id: I4a92477a6eeaa9a11fd710d35c602d8d6f88cbb6
Signed-off-by: Dmitry Petrochenko <dmitry.petrochenko@intel.com>
diff --git a/compiler/dex/frontend.cc b/compiler/dex/frontend.cc
index cc616f6..e48e5bf 100644
--- a/compiler/dex/frontend.cc
+++ b/compiler/dex/frontend.cc
@@ -160,6 +160,7 @@
   // TODO: x86_64 & arm64 are not yet implemented.
   DCHECK((cu.instruction_set == kThumb2) ||
          (cu.instruction_set == kX86) ||
+         (cu.instruction_set == kX86_64) ||
          (cu.instruction_set == kMips));