pgsql: Refix the unaccent regression test on MSVC properly

Refix the unaccent regression test on MSVC properly

... for some value of "properly". Instead of overriding REGRESS_OPTS,
set the variables ENCODING and NO_LOCALE, which is more expressive and
allows overriding by the user. Fix vcregress.pl to handle that.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/385942f46ce526000d231c51c76360a807c2f809

Modified Files
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contrib/unaccent/Makefile | 5 +++--
src/tools/msvc/vcregress.pl | 8 ++++++++
2 files changed, 11 insertions(+), 2 deletions(-)