bpo-40014: Fix os.getgrouplist() (GH-19126)

bpo-40014: Fix os.getgrouplist() (GH-19126)

Fix os.getgrouplist(): if getgrouplist() function fails because the
group list is too small, retry with a larger group list.

On failure, the glibc implementation of getgrouplist() sets ngroups
to the total number of groups. For other implementations, double the
group list size.
(cherry picked from commit f5c7cabb2be4e42a5975ba8aac8bb458c8d9d6d7)

Co-authored-by: Victor Stinner <vstinner@python.org>