[sssd PR#5228][comment] Test: Add back removed tests

[elkoniu]

URL: https://github.com/SSSD/sssd/pull/5228
Title: #5228: Test: Add back removed tests

elkoniu commented:
"""
Mentioned commit (bdf422f) removed in total 4 tests:
test_users_by_filter_valid()
test_users_by_filter_multiple_domains_valid()
test_groups_by_filter_valid()
test_groups_by_filter_multiple_domains_valid()

Your PR restored 2 of 4 removed tests. What with other two? They are unrelated / deprecated or material for other PR? Or if it is worth to restore them too as they were removed together?
"""

See the full comment at https://github.com/SSSD/sssd/pull/5228#issuecomment-661355096