Refactor cudf::strings::count_re API to use count_matches utility

[davidwendt]

Refactors the cudf::strings::detail::count_re function to reuse the cudf::strings::detail::count_matches utility created for findall, extractall, and split. The kernel code was identical with the only main difference the size of the output column. So the output size was added as a parameter to count_matches and the callers appropriately updated.

[codecov]

Codecov Report

Merging #10580 (185ccdc) into branch-22.06 (26c1810) will increase coverage by 0.01%.
The diff coverage is n/a.

❗ Current head 185ccdc differs from pull request most recent head 01aa70f. Consider uploading reports for the commit 01aa70f to get more accurate results

@@               Coverage Diff                @@
##           branch-22.06   #10580      +/-   ##
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+ Coverage         86.31%   86.33%   +0.01%     
================================================
  Files               140      140              
  Lines             22280    22280              
================================================
+ Hits              19232    19236       +4     
+ Misses             3048     3044       -4     

Impacted Files	Coverage Δ
python/cudf/cudf/core/column/string.py	89.10% <0.00%> (+0.12%)	⬆️
python/cudf/cudf/core/groupby/groupby.py	91.72% <0.00%> (+0.22%)	⬆️
python/cudf/cudf/core/tools/datetimes.py	84.49% <0.00%> (+0.30%)	⬆️
python/cudf/cudf/core/column/lists.py	90.62% <0.00%> (+0.44%)	⬆️

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[bdice]

Nice work! Looks good to me. 👍

[vyasr]

I have a couple of suggestions, but nothing blocking. Feel free to address or not depending on what you think.

[davidwendt]

@gpucibot merge