7019689: Non-dependent name is found in dependent base class although it should be rejected

Fix hashtable.hpp to qualify non-dependant name with "this"

Reviewed-by: phh, never, poonam

hotspot/src/share/vm/utilities/hashtable.hpp

@@ -276,7 +276,7 @@ public:
   }
 
   int index_for(Symbol* name, Handle loader) {
-    return hash_to_index(compute_hash(name, loader));
+    return this->hash_to_index(compute_hash(name, loader));
   }
 };