test: don't connect to :: (use localhost instead)

If a test does http.listen(0) or net.listen(0),
http.listen(0).address().address returns '::'. Some machines will
resolve this to localhost, but not all. Every machine should have
localhost defined in /etc/hosts (or equivalent), so it should always
resolve.

Fixes: https://github.com/nodejs/node/issues/7291
PR-URL: https://github.com/nodejs/node/pull/10854


Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michal Zasso <targos@protonmail.com>