[2.7] bpo-30418: Popen.communicate() always ignore EINVAL (#2002)

[vstinner]

On Windows, subprocess.Popen.communicate() now also ignore EINVAL
on stdin.write() if the child process is still running but closed the
pipe.
(cherry picked from commit d52aa31)

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (2.7@536209e). Click here to learn what that means.
The diff coverage is n/a.

@@          Coverage Diff           @@
##             2.7    #2006   +/-   ##
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  Coverage       ?   83.67%           
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  Files          ?     1371           
  Lines          ?   347317           
  Branches       ?        0           
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  Hits           ?   290621           
  Misses         ?    56696           
  Partials       ?        0

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