Add aarch64 to the architectures without alignment restrictions.

Change-Id: I1ebc76b7ed08e177e97cd1e4d866347b7600057b
diff --git a/luni/src/main/native/libcore_io_Memory.cpp b/luni/src/main/native/libcore_io_Memory.cpp
index 2cef410..9edbfb8 100644
--- a/luni/src/main/native/libcore_io_Memory.cpp
+++ b/luni/src/main/native/libcore_io_Memory.cpp
@@ -38,8 +38,8 @@
 #define LONG_ALIGNMENT_MASK 0x7
 #define INT_ALIGNMENT_MASK 0x3
 #define SHORT_ALIGNMENT_MASK 0x1
-#elif defined(__i386__) || defined(__x86_64__)
-// x86 can load anything at any alignment.
+#elif defined(__aarch64__) || defined(__i386__) || defined(__x86_64__)
+// These architectures can load anything at any alignment.
 #define LONG_ALIGNMENT_MASK 0x0
 #define INT_ALIGNMENT_MASK 0x0
 #define SHORT_ALIGNMENT_MASK 0x0