test: remove unnecessary V8 flag

Refs: https://chromium-review.googlesource.com/c/v8/v8/+/2741582

PR-URL: https://github.com/nodejs/node/pull/37671


Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>