pgsql: Update "pg_regress --no-locale" for Darwin and Windows.

Update "pg_regress --no-locale" for Darwin and Windows.

Commit 894459e59ffa5c7fee297b246c17e1f72564db1d revealed this option to
be broken for NLS builds on Darwin, but "make -C contrib/unaccent check"
and the buildfarm client rely on it. Fix that configuration by
redefining the option to imply LANG=C on Darwin. In passing, use LANG=C
instead of LANG=en on Windows; since only postmaster startup uses that
value, testers are unlikely to notice the change. Back-patch to 9.0,
like the predecessor commit.

Branch
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REL9_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/5596432ec02259d5a37c2ad7df93ee6958b2d5d8

Modified Files
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src/test/regress/pg_regress.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)