netstat: reduce use of historical Internet classes

When attempting to characterize bound addresses, netstat was checking
for host 0 on a (historical) net using inet_lnaof(). Such addresses
are not normally bound, as they would not work, with the exception
of the unspecified address, INADDR_ANY. Check for that explicitly.
Similarly, don't check bound addresses for a match to a network name.

MFC after: 1 month
Reviewed by: tuexen
Differential Revision: https://reviews.freebsd.org/D32714