test: check parameter type of fs.mkdir()

Added tests to check parameter type of fs.mkdir(), fs.mkdirSync()
and fsPromises.mkdir() to increase coverage.

PR-URL: https://github.com/nodejs/node/pull/22616


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: George Adams <george.adams@uk.ibm.com>