test: add tests for process.initgroups

- test argument validation
- test function throws if provided group is invalid

PR-URL: https://github.com/nodejs/node/pull/24154


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>