test: simplify output handling in repl tests

Replace .map() + .replace().trim() with a single .replace().

PR-URL: https://github.com/nodejs/node/pull/11124


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Italo A. Casas <me@italoacasas.com>