tests: Produce predictable results in nsstest

tests: Produce predictable results in nsstest

Problem is that in the test any status file matching
tests/nssdata/*.status is loaded as it contains IP addresses that
are parsed. However, there's no order specified in which the
files are loaded. Therefore on different systems the order may be
different. This is then producing an unexpected results.
Instead of defining an order in which the files are loaded, make
the code that checks for missing IP addresses (or redundant ones)
cope with unordered list of addresses. The reasoning behind is
that the code doing the parsing is used in real NSS module where
we don't care for ordering.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>