[Bug libstdc++/90787] filesystem tests fail if file permissions are not supported

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90787

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P4

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Running the tests as root is a terrible idea of course, but it happens in some
containerized CI environments. And the tests fail on Windows anyway, so fixing
it will avoid FAIL results for mingw targets too.

I'll look into this for GCC 11 stage 1.