Fix the calling convention bug where we didn't account for Method*.

Change-Id: Ic54f0a3e15377d7f161fa3d719eb762f969ef729
diff --git a/src/calling_convention_arm.cc b/src/calling_convention_arm.cc
index 9c7ba6f..78f0c6c 100644
--- a/src/calling_convention_arm.cc
+++ b/src/calling_convention_arm.cc
@@ -68,7 +68,9 @@
 
 FrameOffset ManagedRuntimeCallingConvention::CurrentParamStackOffset() {
   CHECK_GE(itr_slots_, 3u);
-  return FrameOffset(displacement_.Int32Value() + (itr_slots_ * kPointerSize));
+  return FrameOffset(displacement_.Int32Value() +   // displacement
+                     kPointerSize +                 // Method*
+                     (itr_slots_ * kPointerSize));  // offset into in args
 }
 
 // JNI calling convention