This new version of the patch provides a workaround for the issue1686475
regression. It simply falls back to the traditional (symlink-naive) stat
behavior when a handle cannot be obtained for the specified filename. 
My intention is that we can commit this patch (as it's still a strict
improvement over the previous behavior), and work out a fully-symlink
aware stat method in a subsequent patch.

There are still regression tests in test_posixpath.py that are failing
due to the non-implementation of realpath. I'll tackle this task next.