test: add test cases for path

Add test cases for the following line.
https://github.com/nodejs/node/blob/0f2f8ef/lib/path.js#L1364
https://github.com/nodejs/node/blob/0f2f8ef/lib/path.js#L1347

PR-URL: https://github.com/nodejs/node/pull/11453


Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>