pgsql: Add vcregress.pl target for checking pg_upgrade.

Add vcregress.pl target for checking pg_upgrade.

This follows recent addition of Windows/Mingw testing.
Backpatch to Release 9.2 so we can get some buildfarm testing
going.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/a1d021e5d2f58170c7900c8766c4633e5f2328ee

Modified Files
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src/tools/msvc/Install.pm | 13 +++++--
src/tools/msvc/vcregress.pl | 82 ++++++++++++++++++++++++++++++++++++++++---
2 files changed, 87 insertions(+), 8 deletions(-)