Ignore all /var/db changes post-install
Ignore all /var/db changes post-install

Mirroring the ports leftover script logic, the only changes to /var/db
that were forgiven were to /var/db/freebsd-update and /var/db/pkg (in
addition to the base /var/db/fontconfig exception).  However, there are
more exceptions than that in practice, e.g. /var/db/mysql, so just
ignore all /var/db changes that occur between staging and package
installation.

This solves databases/mysql56-server and similar test failures.

jrmarino/synth,jrmarino/synth,jrmarino/synth,jrmarino/synth