Junctions and symlinks are not properly handled by vfs.dir.size on Windows

Create two directories which contains symlinks or junctions (created with mklink) to each other. While apparently there are some safeguards (or just luck?) in Windows and it will not result in infinite recursion, it does loop 70+ times and gives incorrect result.

On *nix systems symlinks are followed only once. However that is done by checking inode, not sure if we can apply similar pattern on Windows. In worst case it would be better to ignore symlinks/juctions on Windows and document it.