POC: Eliminate unnecessary group by keys (q35 in clickbench 1.35x faster)

[Rachelint]

Which issue does this PR close?

Closes #.

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[Rachelint]

It is really effective for query like q35 in clickbench.

// Before
Q35: SELECT "ClientIP", "ClientIP" - 1, "ClientIP" - 2, "ClientIP" - 3, COUNT(*) AS c FROM hits GROUP BY "ClientIP", "ClientIP" - 1, "ClientIP" - 2, "ClientIP" - 3 ORDER BY c DESC LIMIT 10;
Query 35 iteration 0 took 2371.1 ms and returned 10 rows

// After
Q35: SELECT "ClientIP", "ClientIP" - 1, "ClientIP" - 2, "ClientIP" - 3, COUNT(*) AS c FROM hits GROUP BY "ClientIP", "ClientIP" - 1, "ClientIP" - 2, "ClientIP" - 3 ORDER BY c DESC LIMIT 10;
Query 35 iteration 0 took 1491.4 ms and returned 10 rows

[Rachelint]

It's late today, plan to sort out codes and add test tomorrow.

[github-actions]

Thank you for your contribution. Unfortunately, this pull request is stale because it has been open 60 days with no activity. Please remove the stale label or comment or this will be closed in 7 days.