Initial changes towards Generic JNI option

Some initial changes that lead to an UNIMPLEMENTED. Works
by not compiling for JNI right now and tracking native methods
which have neither quick nor portable code. Uses new trampoline.

Change-Id: I5448654044eb2717752fd7359f4ef8bd5c17be6e
diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index 88dbb9c..e31a6cd 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -351,6 +351,10 @@
     return portable_resolution_trampoline_;
   }
 
+  const void* GetQuickGenericJniTrampoline() const {
+      return quick_generic_jni_trampoline_;
+    }
+
   const void* GetQuickResolutionTrampoline() const {
     return quick_resolution_trampoline_;
   }
@@ -643,6 +647,7 @@
   const void* quick_resolution_trampoline_;
   const void* portable_imt_conflict_trampoline_;
   const void* quick_imt_conflict_trampoline_;
+  const void* quick_generic_jni_trampoline_;
 
   friend class ImageWriter;  // for GetClassRoots
   FRIEND_TEST(ClassLinkerTest, ClassRootDescriptors);