The RI returned an empty PropertyIterator when Node.getReferences was
called on a Node that isn't referenceable.
However, Node.getWeakReferences threw UnsupportedRepositoryOperation which
i modified to empty PropertyIterator as well .
As stated in the issue, i had a quick look at the javadoc and couldn't find
what was the expected behavior.
Not throwing feels better to me and i would suggest to state that in the
(I didn't check the specification though...)