stream: add a non-destroying iterator to Readable

add a non-destroying iterator to Readable

fixes: https://github.com/nodejs/node/issues/38491

PR-URL: https://github.com/nodejs/node/pull/38526
Fixes: https://github.com/nodejs/node/issues/38491


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Robert Nagy <ronagy@icloud.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>