STYLE: Run Isort on tests-> util, series, arrays

[thoo]

• partial Fix import formatting using isort #23334
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
  Run isort on some leftover files from tests/util, tests/arrays and tests/series.

[pep8speaks]

Hello @thoo! Thanks for submitting the PR.

• There are no PEP8 issues in the file pandas/tests/arrays/categorical/test_missing.py !

• There are no PEP8 issues in the file pandas/tests/arrays/categorical/test_sorting.py !

• There are no PEP8 issues in the file pandas/tests/arrays/test_datetimelike.py !

• There are no PEP8 issues in the file pandas/tests/arrays/test_integer.py !

• There are no PEP8 issues in the file pandas/tests/series/test_duplicates.py !

• There are no PEP8 issues in the file pandas/tests/util/test_hashing.py !

• There are no PEP8 issues in the file pandas/tests/util/test_testing.py !

• There are no PEP8 issues in the file pandas/tests/util/test_util.py !

[datapythonista]

lgtm

thanks @thoo

[codecov]

Codecov Report

Merging #23501 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #23501   +/-   ##
=======================================
  Coverage   92.23%   92.23%           
=======================================
  Files         161      161           
  Lines       51197    51197           
=======================================
  Hits        47220    47220           
  Misses       3977     3977

Flag	Coverage Δ
#multiple	90.61% <ø> (ø)	⬆️
#single	42.27% <ø> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 24ab22f...295febf. Read the comment docs.

[jreback]

thanks!

[alimcmaster1]

thanks! @thoo