Show ArtMethods in imgdiag

Since ArtMethods were moved out of mirror:: classes imgdiag does not
show information about them.  Diff ArtMethods to facilitate finding
dirty memory there.

Bug: 38173645
Test: imgdiag --boot-image=/system/framework/boot.art --image-diff-pid=`pid system_server`
Change-Id: Icd86a9ef14d5177a297026c22c81c080f5c85fc1
diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index 9727adf..2f92da3 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -500,6 +500,9 @@
   // Is the given entry point quick code to run the generic JNI stub?
   bool IsQuickGenericJniStub(const void* entry_point) const;
 
+  // Is the given entry point the JNI dlsym lookup stub?
+  bool IsJniDlsymLookupStub(const void* entry_point) const;
+
   const void* GetQuickToInterpreterBridgeTrampoline() const {
     return quick_to_interpreter_bridge_trampoline_;
   }