Check that the numbers of *versions* output is equal to the number of pkgconf's

fixes #8923

The pkgconf behavior was reverted upstream in 2.0

(this should cover the case too of checking that equal pkgList lines are output also)

(cherry picked from commit 3832beaf)

# Conflicts:
#	cabal-install-solver/src/Distribution/Solver/Types/PkgConfigDb.hs