stream: always defer readable in EOF when sync

Fix a regression introduced by
https://github.com/nodejs/node/pull/18515 that broke
the dicer module tests.

See: https://github.com/nodejs/node/pull/18515

PR-URL: https://github.com/nodejs/node/pull/18615


Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>