Disable jit for ARM 64 bit

Until issues are fixed.

Bug: 17950037
Change-Id: I4517a1e188adf0a087576423066c348eb6ae81be
diff --git a/runtime/jit/jit.cc b/runtime/jit/jit.cc
index 9b89459..897287b 100644
--- a/runtime/jit/jit.cc
+++ b/runtime/jit/jit.cc
@@ -32,6 +32,9 @@
 namespace jit {
 
 JitOptions* JitOptions::CreateFromRuntimeArguments(const RuntimeArgumentMap& options) {
+  if (kRuntimeISA == kArm64) {
+    return nullptr;
+  }
   if (!options.GetOrDefault(RuntimeArgumentMap::UseJIT)) {
     return nullptr;
   }