Make sure we validate the port number in all kinds of `listen()` calls.
Fixes: https://github.com/nodejs/node/issues/5727
PR-URL: https://github.com/nodejs/node/pull/5732
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>