find_nth() will be inefficient on a trie. Since find_nth() is only used
internally and only for enumerating properties, we can add a foreach()
function to do this directly.
Signed-off-by: Greg Hackmann <ghackmann@google.com>
(cherry picked from commit 577418403d68e663fb33c7b0c8a90d862d9c00cf)
Change-Id: Iaca97d1182ce2c28863ba85241cbb5cf6185eb2f