MDEV-18479: Avoid COST_MULT(records, 1)

sql/sql_select.cc

@@ -3856,11 +3856,8 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
         table/view.
       */
       for (i= 0; i < join->table_count ; i++)
-      {
-        records= COST_MULT(records,
-                           join->best_positions[i].records_read ?
-                           join->best_positions[i].records_read : 1);
-      }
+        if (double rr= join->best_positions[i].records_read)
+          records= COST_MULT(records, rr);
       ha_rows rows= records > HA_ROWS_MAX ? HA_ROWS_MAX : (ha_rows) records;
       set_if_smaller(rows, unit->select_limit_cnt);
       join->select_lex->increase_derived_records(rows);