adding another set of test for disjunction
adding another set of test for disjunction

Previous set of tests did not correctly check the combinations of
disjunction and route constraint. This new set tests specific cases
with several demands in one synchronization vector with and without
route constraint, and the case where both disjunction constraint and
route can not be met (STRICT and LOOSE cases)

+ minor refactor on test_disjunction

Signed-off-by: EstherLerouzic <9136e9bbec0a09a1685b8ebbe677b6c9b26e8f18@orange.com>
Change-Id: Id5a5902e6945185922ce5743ac97d15dbc777af2

Telecominfraproject/gnpy