Make fast JNI part of pretty method output.

Change-Id: Ic4951a22d12e93d7f1e1af7ffbb08b4bb9b8f587
diff --git a/runtime/utils.cc b/runtime/utils.cc
index 950e3f9..2ad4c4a 100644
--- a/runtime/utils.cc
+++ b/runtime/utils.cc
@@ -358,13 +358,16 @@
 }
 
 std::string PrettyMethod(const mirror::ArtMethod* m, bool with_signature) {
-  if (m == NULL) {
+  if (m == nullptr) {
     return "null";
   }
   MethodHelper mh(m);
   std::string result(PrettyDescriptor(mh.GetDeclaringClassDescriptor()));
   result += '.';
   result += mh.GetName();
+  if (UNLIKELY(m->IsFastNative())) {
+    result += "!";
+  }
   if (with_signature) {
     const Signature signature = mh.GetSignature();
     std::string sig_as_string(signature.ToString());