Make PG_TEST_USE_UNIX_SOCKETS work for tap tests on windows.
We need to replace windows-style \ path separators with / when putting socket
directories either in postgresql.conf or libpq connection strings, otherwise
they are interpreted as escapes.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Discussion: https://postgr.es/m/
4da250a5-4222-1522-f14d-
8a72bcf7e38e@enterprisedb.com