[3.15] gh-80198: Improve test_pwd and test_grp (GH-150380) (GH-150398)

[3.15] gh-80198: Improve test_pwd and test_grp (GH-150380) (GH-150398)

Fix tests for non-existing names and ids when getpwall()/getgrall()
don't return all users/groups.

Add tests for out-of-range uids, integer float ids, bytes names,
null-terminated names, names with surrogates, empty names, excessive
arguments.
(cherry picked from commit 46e8f7a9e794bfb0fdc5ee82348623eb2b91a0b5)