test: remove common.fileExists()

common.fileExists() can be replaced with fs.existsSync().

PR-URL: https://github.com/nodejs/node/pull/22151


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Weijia Wang <starkwang@126.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>