This uilds on the same way of checking for availability as we do in
TLSProxy.  We use all IP factories we know of, starting with those who
know both IPv6 and IPv4 and ending with the one that only knows IPv4
and cache their possible success as foundation for checking the
available of each IP domain.

80-test_ssl.t has bigger chances of working on platforms that do not
run both IP domains.
Reviewed-by: NRich Salz <rsalz@openssl.org>