net: remove hot path comment from connect

This comment was added with an assumption that we could determine the
IP address that localhost should resolve to without performing a
lookup. This was a false assumption and should be removed.

PR-URL: https://github.com/nodejs/node/pull/4648


Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>