Even if there are no other segments in the line chain, we still should
check for arc connections in cases of individual arcs on a line chain
(cherry picked from commit 6b915049d1)
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