RT #46267 introduced a couple of useful system tests, but it was only
applied to master.  The same branch also fixed RT #46055 (which was
merged with #46077, from which RT #46267 was split off), which means the
fix has not been backported to maintenance branches.

However, the differences between master and older branches will require
tweaking certain tests, removing some of them altogether and other
customizations.  This effort will be tracked in this ticket.