Review Mozilla 1769994: On systems with IPv6 preferred DNS resolution clients will fail to connect when "localhost" is used as host for the WebSocket server

Link: https://bugzilla.mozilla.org/show_bug.cgi?id=1769994

Found via the code audit, particularly gecko-dev commit c193147b7b622a9b69e768079553e0d27c05c993 with title 'Resolve localhost to an IP before starting httpd.js'