test: mark test-policy-integrity flaky on Windows

Ref: https://github.com/nodejs/node/issues/40694

PR-URL: https://github.com/nodejs/node/pull/40684


Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Voltrex <mohammadkeyvanzade94@gmail.com>