this PR support slot appearing both in agg func and grouping sets.
sql like below:
select sum(a) from t group by grouping sets ((a));
Before this PR, Nereids throw exception like below:
col_int_undef_signed cannot both in select list and aggregate functions when using GROUPING SETS/CUBE/ROLLUP, please use union instead.
This PR removes the restriction and supports this situation.
1. create a project node to adjust the output column position when a mv is selected in olap scan node
2. pass SlotReference's column info when call Alias's toSlot() method
3. should compare plan's logical properties when compare two plans after rewrite
Result of functions grouping and grouping_id is always not nullable, but outer join will convert the result column to nullable when necessary, which will cause mismatch of column type and column object when executing unctions grouping and grouping_id.
