child_process: only stop readable side of stream passed to proc

Closing the underlying resource completely has the unwanted side effect
that the stream can no longer be used at all, including passing it
to other child processes.

What we want to avoid is accidentally reading from the stream;
accordingly, it should be sufficient to stop its readable side
manually, and otherwise leave the underlying resource intact.

Fixes: https://github.com/nodejs/node/issues/27097
Refs: https://github.com/nodejs/node/pull/21209

PR-URL: https://github.com/nodejs/node/pull/27373


Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>