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
------
REL9_2_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/4c25df55fdf4f0be071d0974e0e5732580807881

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