[Bug 51443] Test fails in remove_dir_all crate when creating file

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=51443

--- Comment #2 from LingM  ---
Er, correction, nothing is fixed with Wine 8.13. The real problem has been the
assert on line 92 firing all along.

What happened is that said assert firing killed the test and so the files it
created didn't get cleaned up. When you run `wine cargo test` a second time the
`readonly` folder it created still exists and you get the `PermissionDenied`
error.