Compile-time specializations for some hashing strategies

[akuzm]

Generate specialized code at compiled time for some vectorized grouping cases such as grouping by a single fixed-value column. This improves performance.

[codecov]

Codecov Report

❌ Patch coverage is 54.54545% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.57%. Comparing base (0f55e9a) to head (af9b5ad).
⚠️ Report is 97 commits behind head on main.

Files with missing lines	Patch %	Lines
.../src/nodes/vector_agg/hashing/hash_strategy_impl.c	54.54%	2 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8269      +/-   ##
==========================================
+ Coverage   82.49%   82.57%   +0.07%     
==========================================
  Files         248      248              
  Lines       47940    47922      -18     
  Branches    12224    12223       -1     
==========================================
+ Hits        39550    39570      +20     
- Misses       3485     3499      +14     
+ Partials     4905     4853      -52     

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[github-actions]

This pull request has been automatically marked as stale due to lack of activity. This pull request will be closed in 30 days.

[github-actions]

This pull request has been automatically marked as stale due to lack of activity. This pull request will be closed in 30 days.