Reuse RACO MyriaL tests as MyriaX integration tests

We should be able to reuse the MyriaL tests in `https://github.com/uwescience/raco/blob/master/raco/myrial/query_tests.py` for MyriaX integration tests if we can somehow plug in MyriaX as the backend (rather than FakeDB). This would require taking a `raco` dependency in our `integration_tests` module.