net: don't normalize twice in Socket#connect()

Split up Socket#connect() so that we don't call normalizeArgs() twice
when invoking net.connect() or net.createConnection().

PR-URL: https://github.com/nodejs/node/pull/12342


Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>