readline: add support for async iteration

Co-authored-by: Ivan Filenko <ivan.filenko@protonmail.com>
Fixes: https://github.com/nodejs/node/issues/18603
Refs: https://github.com/nodejs/node/pull/18904
PR-URL: https://github.com/nodejs/node/pull/23916


Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>