test: fix invalid `file:` URL in `test-fs-path-dir`

[aduh95]

Trying to build a URL by concatenating file:// and a path will always fail as soon as the path contains some URL-significant char (e.g. %, ?, #)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 88.41%. Comparing base (7ae193d) to head (ee6d1bd). Report is 268 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #55454   +/-   ##
=======================================
  Coverage   88.40%   88.41%           
=======================================
  Files         653      653           
  Lines      187600   187505   -95     
  Branches    36117    36100   -17     
=======================================
- Hits       165854   165777   -77     
+ Misses      14974    14967    -7     
+ Partials     6772     6761   -11     

see 37 files with indirect coverage changes

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/63198/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/63199/

[nodejs-github-bot]

Landed in 7e60b5e15b4549712009fe10d080777b7852eb71

[ruyadorno]

This commit does not land cleanly on v22.x-staging and will need manual backport in case we want it in v22.x.