Rollup merge of #65685 - oxalica:statx-eperm, r=alexcrichton

Fix check of `statx` and handle EPERM

Should fix #65662

https://github.com/rust-lang/rust/issues/65662#issuecomment-544593939
> I think a reasonable solution might be to do something like try to stat AT_CWD initially and if that fails with EPERM or ENOSYS we disable the syscall entirely, otherwise it's cached as always good to use.

r? @alexcrichton