test: improve coverage for process.umask

This ensures that process.umask() throws with the correct error when
invalid inputs are supplied.

PR-URL: https://github.com/nodejs/node/pull/16188


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>