AArch64: Add arm64 runtime support.

Adds support for arm64 to ART. Assembler stubs are sufficient for
down calls into interpreter. JNI compiler and generics are not finished.

Basic Generic JNI functionality.

Change-Id: I4a07c79d1e037b9f5746673480e32cf456867b82
diff --git a/build/Android.common.mk b/build/Android.common.mk
index 219f1e2..d80d039 100644
--- a/build/Android.common.mk
+++ b/build/Android.common.mk
@@ -17,7 +17,7 @@
 ifndef ANDROID_COMMON_MK
 ANDROID_COMMON_MK = true
 
-ART_SUPPORTED_ARCH := arm mips x86 x86_64
+ART_SUPPORTED_ARCH := arm arm64 mips x86 x86_64
 
 ifeq (,$(filter $(TARGET_ARCH),$(ART_SUPPORTED_ARCH)))
 $(warning unsupported TARGET_ARCH=$(TARGET_ARCH))