pgsql: Further tighten Windows CRLF conversion in our TAP test scripts.

Further tighten Windows CRLF conversion in our TAP test scripts.

Buildfarm results now imply that Perl's IPC::Run does CRLF conversion
for us if we're using native Perl, but not when using MSys Perl.
Restrict the conversions done by PostgresNode.pm to act only in the
latter case.  (Similar conversions done in TestLib.pm and RewindTest.pm
were already handled this way.)

Discussion: https://postgr.es/m/412ae8da-76bb-640f-039a-f3513499e53d@gmx.net

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/ffb4cee43bdccb54f0cf072a51dedc74e343b6f1

Modified Files
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src/test/perl/PostgresNode.pm | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)