support "with rollup"

If you use 'with rollup' syntax then the following error is returned by default:

MariaDB [flights]> select carrier, count(*) from flights group by carrier with rollup;

ERROR 1178 (42000): The storage engine for the table doesn't support IDB-1014: Rollup is currently not supported.

This can be worked around by specifying non distributed query operating mode as documented here: https://mariadb.com/kb/en/mariadb/columnstore-operating-mode/

 set infinidb_vtable_mode=0;

Testing the changes

The behavior of WITH ROLLUP is the same with regard to types of rolled up GROUP BY columns. E.g., if we GROUP BY on TEXT and TEXT columns, the behavior ith regards to adding rows with NULLs should be the same as with INTEGER and INTEGER columns.

The aggregates we definitely must support; MIN, MAX, SUM, AVG, COUNT (both forms).

The aggregates we do not support right now: GROUP_CONCAT and JSONARRAYAGG.

Any other may or may not work.