branches/zip: dict_table_check_for_dup_indexes(): Assert that the

data dictionary mutex is being held while table->indexes is accessed.
This is already the case.

Currently, only dict_table_get_next_index() and dict_table_get_first_index()
are being invoked without holding dict_sys->mutex.

dict/dict0dict.c

@@ -4775,6 +4775,8 @@ dict_table_check_for_dup_indexes(
 	const dict_index_t*	index1;
 	const dict_index_t*	index2;
 
+	ut_ad(mutex_own(&dict_sys->mutex));
+
 	/* The primary index _must_ exist */
 	ut_a(UT_LIST_GET_LEN(table->indexes) > 0);