Attempt to make FreeBSD testsuite-green
This includes various bits from my attempt to make FreeBSD pass the testsuite:
- !13618 (closed)
- !13617 (closed)
- Various testing infrastructure changes
The runner configuration is documented in https://gitlab.haskell.org/bgamari/ghc-utils/-/blob/master/rel-eng/setting-up-freebsd.mkd?ref_type=heads.
Edited by Ben Gamari