test: fix test_tree_with_broken_symlinks on Python 3.13 https://docs.python.org/3/library/pathlib.html#pathlib.Path.resolve says:
_Changed in version 3.13:_ Symlink loops are treated like other errors: `OSError` is raised in strict mode, and no exception is raised in non-strict mode. In previous versions, `RuntimeError` is raised no matter the value of _strict_.
