AArch64: Implicit StackOverflow/NPE/Suspend checks.

This implements implicit stack overflow checks and null pointer exceptions
for AArch64.  Suspend checks are implemented but not switched on yet.

Change-Id: I2eb076f2c0c9d94793d5a898fea49cf409b4eb66
Signed-off-by: Stuart Monteith <stuart.monteith@arm.com>
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index 2c25c2c..fe877d5 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -620,6 +620,7 @@
     case kArm:
     case kThumb2:
     case kX86:
+    case kArm64:
       implicit_null_checks_ = true;
       implicit_so_checks_ = true;
       break;