pgsql: Ensure the right perl is used for TAP tests on msys

Ensure the right perl is used for TAP tests on msys

In particular, perl with $Config{osname} = msys should only be used if
the build target is msys (which is currently buildable but not usable).
For builds targeted at native Windows, perl from the ucrt64 toolchain is
suitable.

Discussion: https://postgr.es/m/20220216210141.5glt5isg5qtwty4c@alap3.anarazel.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/cf12541f2bd5fd34425ecbb99f056a30ca5b7cae

Modified Files
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config/check_modules.pl | 5 +++++
configure               | 1 +
configure.ac            | 1 +
3 files changed, 7 insertions(+)