ha_innobase::external_lock(): Update prebuilt->mysql_has_locked and

trx->n_mysql_tables_in_use only after row_lock_table_for_mysql()
returns DB_SUCCESS.  A timeout on LOCK TABLES would lead to an
inconsistent state, which would cause trx_free() to print a warning.

This was later reported as Bug #31444.

handler/ha_innodb.cc

@@ -6456,9 +6456,6 @@ ha_innobase::external_lock(
 			innobase_register_stmt(ht, thd);
 		}
 
-		trx->n_mysql_tables_in_use++;
-		prebuilt->mysql_has_locked = TRUE;
-
 		if (trx->isolation_level == TRX_ISO_SERIALIZABLE
 			&& prebuilt->select_lock_type == LOCK_NONE
 			&& thd_test_options(thd,
@@ -6507,6 +6504,9 @@ ha_innobase::external_lock(
 			trx->mysql_n_tables_locked++;
 		}
 
+		trx->n_mysql_tables_in_use++;
+		prebuilt->mysql_has_locked = TRUE;
+
 		DBUG_RETURN(0);
 	}