[3.12] Fix iter_index() to work with lists which do not support stop=None. (gh-109306) (#109310)

Fix iter_index() to work with lists which do not support stop=None. (gh-109306)
(cherry picked from commit f2a55fecd063244a5fd09a38f673f0781f8802d1)

Co-authored-by: Raymond Hettinger <rhettinger@users.noreply.github.com>