Noticed that issue while reviewing #275633: when declaring
`ListenAddress host` without a port, all ports declared by
`Port`/`cfg.ports` will be used with `host` according to
`sshd_config(5)`.
However, if this is done and socket activation is used, only a socket
for port 22 is created instead of a sockets for each port from
`Port`/`cfg.ports`. This patch corrects that behavior.
Also added a regression test for this case.
7e45990c06