repl: fix declaring a variable with the name `util`

The REPL no longer relies on `util` being a reference to the `util` core
module. It still relies on `globalThis` refering to the global object,
but no longer emits warnings when it's overwritten by the user.

PR-URL: https://github.com/nodejs/node/pull/38141
Fixes: https://github.com/nodejs/node/issues/38139


Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>