pgsql: Re-enable TAP tests of pg_receivewal for ZLIB on Windows

Re-enable TAP tests of pg_receivewal for ZLIB on Windows

This is a revert of 6cea447, that disabled those tests temporarily on
Windows due to failures with bowerbird where gzflush() would fail when
executed on a freshly-opened compressed and partial segment.  This
problem should be taken care of now thanks to 7fbe0c8, so let's see what
the buildfarm has to say on Windows for those tests.

Discussion: https://postgr.es/m/YPDLz2x3o1aX2wRh@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/91d395f47aa92849b2556b1a4d6bc1ff34121a30

Modified Files
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src/bin/pg_basebackup/t/020_pg_receivewal.pl | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)