test: improve checks in test-path-parse-format

- validate full error messages
- use assert.throws() instead of try...catch

PR-URL: https://github.com/nodejs/node/pull/11223


Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>