Issue 5177609: remove Monitor(Enter|Exit)Helper

Add necessary indirection for synchronized native methods that
lock/unlock the object/class using the regular JNI MonitorEnter/Exit
functions.

Change-Id: I00cda7284fcfa09e1218ddbfb1e24ea4aaa94ac3
diff --git a/src/assembler_arm.h b/src/assembler_arm.h
index 99ff9fe..bad3023 100644
--- a/src/assembler_arm.h
+++ b/src/assembler_arm.h
@@ -431,6 +431,7 @@
 
   void CopyRef(FrameOffset dest, FrameOffset src, ManagedRegister scratch);
   void LoadRef(ManagedRegister dest, ManagedRegister base, MemberOffset offs);
+  void LoadRawPtr(ManagedRegister dest, ManagedRegister base, Offset offs);
 
   void StoreImmediateToFrame(FrameOffset dest, uint32_t imm,
                              ManagedRegister scratch);