We were calculating the same thing in three locations and we missed
adding the clearance from the footprints in, resulting in bad fills and
missed drc errors (see QA addition)
The RegressionZoneFillTests handle issues that are resolved by the zone
filler, so Clipper2 problematic fill belongs there. Otherwise, the
remaining tests should not refill the zones before running DRC because
we expect the DRC to catch errors without needing a refill