Cleanup regex compile optimize functions

[davidwendt]

Cleans up the internal regcomp::optimize1() function by replacing for-loops with STL functions. Hopefully this will make this part of the code a bit easier to understand and maintain.

No external function or behavior has changed.

[codecov]

Codecov Report

Merging #10825 (ef17bb9) into branch-22.06 (8d861ce) will decrease coverage by 0.08%.
The diff coverage is 94.84%.

❗ Current head ef17bb9 differs from pull request most recent head 7982923. Consider uploading reports for the commit 7982923 to get more accurate results

@@               Coverage Diff                @@
##           branch-22.06   #10825      +/-   ##
================================================
- Coverage         86.40%   86.31%   -0.09%     
================================================
  Files               143      144       +1     
  Lines             22448    22648     +200     
================================================
+ Hits              19396    19549     +153     
- Misses             3052     3099      +47     

Impacted Files	Coverage Δ
python/cudf/cudf/core/column/string.py	88.78% <ø> (-0.31%)	⬇️
python/cudf/cudf/core/frame.py	93.41% <ø> (ø)
python/cudf/cudf/core/indexed_frame.py	91.70% <ø> (ø)
python/cudf/cudf/io/__init__.py	100.00% <ø> (ø)
python/cudf/cudf/testing/testing.py	81.81% <50.00%> (+0.12%)	⬆️
python/cudf/cudf/io/parquet.py	90.83% <86.60%> (-1.87%)	⬇️
python/cudf/cudf/core/index.py	92.06% <88.88%> (-0.25%)	⬇️
python/cudf/cudf/core/scalar.py	89.01% <90.90%> (-0.31%)	⬇️
python/cudf/cudf/core/dataframe.py	93.78% <96.36%> (+0.08%)	⬆️
python/cudf/cudf/__init__.py	90.69% <100.00%> (+0.22%)	⬆️
... and 30 more

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[harrism]

Nice modernization!

[bdice]

LGTM!

[davidwendt]

@gpucibot merge