ping: By default, don't reverse lookup IP addresses

ping's default is now not to attempt reverse DNS lookups. The -H flag will
enable them. This change is not quite a reversion of r351330. That change
made the happy path and error path do reverse lookups consistently; this
change changes the default for both paths.

Submitted by: Ján Sučan <sucanjan@gmail.com>
Discussed with: cem
MFC after: 2 weeks
MFC-With: 351330
Sponsored by: Google LLC (Google Summer of Code 2019)
Differential Revision: https://reviews.freebsd.org/D21364