Group-by aggregation based optimization for UNBOUNDED collect_set window function

[mythrocks]

Fixes #10114.

This change introduces an optimization for the collect_set() window function, when run as an fully UNBOUNDED window function, as follows:

SELECT COLLECT_SET(foo) OVER (PARTITION BY grp 
                              ORDER BY ord 
                              ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) ... 

It might be possible to solve most UNBOUNDED window aggregations via group-wise aggregations. This change addresses collect_set first.

This change currently builds on the changes @revans2 made over at #10158, and includes those changes here.

A new window-exec is introduced specifically to address fully UNBOUNDED window functions. Each input batch is processed via group-wise aggregations. For groups that are known to be complete, the output is returned. The results for incomplete groups are cached, and finalized only when the end of the group is encountered.

[mythrocks]

Sorry, I thought I'd upmerged.

Yes, I should resolve these before we merge.

[revans2]

Still getting errors on compile. Looks like some style issues with the imports.

[revans2]

I did some quick scale tests and it looks really good. I'll try to look through all of the code on Monday.

[mythrocks]

Build

[mythrocks]

Build

[mythrocks]

Build

[mythrocks]

CI still seems to be failing because of #10382. I'll retry the build after #10382 is resolved.

[mythrocks]

Build

[mythrocks]

Build

[mythrocks]

@revans2: I've rebased this change since #10158 was merged. The tests are passing, thankfully.