windows wasi: rmdir on symlink to dir succeeds

[wingo]

To repro:

    dir.symlink_at(".".to_string(), "dot".to_string()).await.unwrap();
    assert_eq!(
        dir.remove_directory_at("dot".to_string()).await,
        Err(ErrorCode::NotDirectory)
    );

Expected result: fails with NotDirectory

On windows, it succeeds: https://github.com/WebAssembly/wasi-testsuite/pull/198/files#r2630813076

[alexcrichton]

Personally I'd say this is a case where the "spec" for wasi:filesystem should be updated to allow for this case. Windows symlinks are pretty different compared to Unix in subtle ways but there's only so much we can do. I don't think it'd be great if we were forced to, for example, test the file's existence in remove-directory-at first before actually trying to remove it.

[wingo]

I keep learning horrible things!!! Agreed that there is no viable workaround. Goddammit.