perf: Use BitmapBuilder in a lot more places

[orlp]

This isn't quite every place yet, but gotta put a cut-off point somewhere for a PR.

[ritchie46]

Hmm.. those coverage tests look related.

[orlp]

@ritchie46 They were. The new BitmapBuilder has a method .into_opt_validity() which returns None if there were no unset bits. The old code could only return Some(bitmap), so it made an unwrap there incorrect.

[codecov]

Codecov Report

Attention: Patch coverage is 88.34951% with 24 lines in your changes missing coverage. Please review.

Project coverage is 79.77%. Comparing base (6753bb6) to head (e6218fe).
Report is 12 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-arrow/src/bitmap/builder.rs	87.62%	12 Missing ⚠️
...rates/polars-compute/src/comparisons/dictionary.rs	0.00%	2 Missing ⚠️
crates/polars-compute/src/gather/generic_binary.rs	0.00%	2 Missing ⚠️
crates/polars-core/src/series/series_trait.rs	0.00%	2 Missing ⚠️
...ates/polars-ops/src/chunked_array/array/any_all.rs	0.00%	2 Missing ⚠️
...rates/polars-ops/src/chunked_array/list/any_all.rs	0.00%	2 Missing ⚠️
crates/polars-compute/src/unique/boolean.rs	50.00%	1 Missing ⚠️
crates/polars-compute/src/unique/primitive.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #20776      +/-   ##
==========================================
+ Coverage   79.74%   79.77%   +0.03%     
==========================================
  Files        1561     1561              
  Lines      222012   221979      -33     
  Branches     2530     2530              
==========================================
+ Hits       177043   177094      +51     
+ Misses      44387    44303      -84     
  Partials      582      582              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.