Some interpreter cleanup.

- Pass result pointer to interpreter to interpreter entry point.
- Avoid using MethodHelper.ChangeMethod in DoInvoke.

Change-Id: I714b78d50fb14d7a0edced54cd4de78ae54021da
diff --git a/src/class_linker.cc b/src/class_linker.cc
index 63d01a9..52ce964 100644
--- a/src/class_linker.cc
+++ b/src/class_linker.cc
@@ -74,7 +74,7 @@
 
 namespace art {
 
-JValue artInterpreterToQuickEntry(Thread* self, ShadowFrame* shadow_frame);
+void artInterpreterToQuickEntry(Thread* self, ShadowFrame* shadow_frame, JValue* result);
 
 static void ThrowNoClassDefFoundError(const char* fmt, ...)
     __attribute__((__format__(__printf__, 1, 2)))