tests: fix error in test_groups caused by paginating

When there are many groups created in previous tests, the group we're
looking for may not in the first page, thus NoSuchElementException will
be raised and cause error in test. Workaround this by searching that
group first.

Change-Id: Ib1754ffa0af0d2bcb86c3f5b9b6f262a5c4d1f43
Merge "tests: fix error in test_groups caused by paginating" into develop