tests: Move test_libraries a bit higher

tests: Move test_libraries a bit higher

In the Makefile in tests/ we initialize couple of variables like
test_programs, test_libraries and test_helpers. These variables
contain all the targets that we need to build in order to run
the test suite. So we initialize test_programs and test_helpers
and then conditionally add targets to them depending on what we
are building with. Then we repeat the same process with
test_libraries. It makes no sense to have two separate if-endif
sequences.

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