src: pass along errors from `--security-reverts`

Pass along errors from `Revert()` when a security revert
is unknown (which currently applies to all possible values).

Previously, we would unconditionally call `exit()`, which is
not nice for embedding use cases, and could crash because we
were holding a lock for a mutex in `ProcessGlobalArgs()` that
would be destroyed by calling `exit()`.

Also, add a regression test that makes sure that the process
exits with the right exit code and not a crash.

PR-URL: https://github.com/nodejs/node/pull/25466


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>