eolian: clear chash on each iteration during validation

This is necessary because inheritance trees need to be validated
individually for proper name conflict checks. It also prevents
eina_hash_add related errors.

src/lib/eolian/database_validate.c

@@ -899,6 +899,7 @@ database_validate(const Eolian_Unit *src)
    EINA_ITERATOR_FOREACH(iter, cl)
      {
         eina_hash_free_buckets(nhash);
+        eina_hash_free_buckets(chash);
         if (!_validate_class(&vals, cl, nhash, chash))
           {
              eina_iterator_free(iter);