MSVC: Revert most 9.5 changes to pre-9.5 vcregress.pl tests.

MSVC: Revert most 9.5 changes to pre-9.5 vcregress.pl tests.

The reverted changes did not narrow the semantic gap between the MSVC
build system and the GNU make build system.  For targets old and new
that run multiple suites (contribcheck, modulescheck, tapcheck), restore
vcregress.pl to mimicking "make -k" rather than the "make -S" default.
Lack of "-k" would be more burdensome than lack of "-S".  Keep changes
reflecting contemporary changes to the GNU make build system, and keep
updates to Makefile parsing.  Keep the loss of --psqldir in "check" and
"ecpgcheck" targets; it had been a no-op when used alongside
--temp-install.  No log message mentioned any of the reverted changes.
Based on a germ by Michael Paquier.  Back-patch to 9.5.