[WIP] remove ci testing for python 2

[tdamsma]

• closes Remove python 2.7 testing #25216
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

[codecov]

Codecov Report

Merging #25217 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #25217      +/-   ##
==========================================
+ Coverage   92.34%   92.35%   +<.01%     
==========================================
  Files         166      166              
  Lines       52314    52314              
==========================================
+ Hits        48311    48312       +1     
+ Misses       4003     4002       -1

Flag	Coverage Δ
#multiple	90.78% <ø> (ø)	⬆️
#single	42.84% <ø> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/util/testing.py	88.05% <0%> (+0.09%)	⬆️

---

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[codecov]

Codecov Report

Merging #25217 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #25217      +/-   ##
==========================================
+ Coverage   92.34%   92.35%   +<.01%     
==========================================
  Files         166      166              
  Lines       52314    52314              
==========================================
+ Hits        48311    48312       +1     
+ Misses       4003     4002       -1

Flag	Coverage Δ
#multiple	90.78% <ø> (ø)	⬆️
#single	42.84% <ø> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/util/testing.py	88.05% <0%> (+0.09%)	⬆️

---

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 683c7b5...eb719e4. Read the comment docs.

[jreback]

FYI there is already #24942 and we are not quite ready to do this.

[tdamsma]

Missed that one, sorry