[TEST] Removed the randomly and continuously failing test for `dis_max` query behaviour

Too many bogus errors like:

FAIL (1:00:22.911) test: Dis Max queries should boost matches in both fields.
                   <"Pinky Elephant"> expected but was
                   <"It's an Albino, Albino, Albino thing!">.
                   @ test/integration/dis_max_queries_test.rb:35:in `block (2 levels) in <class:DisMaxQueriesIntegrationTest>'