Fixes the scheduled tests

• Make the test case generate samples from the prior
• Force the marginalized likelihood test to use fixed m1 and m2 to ensure no samples are generated with the wrong ordering
• Remove pipenv

.gitlab-ci.yml

@@ -79,18 +79,9 @@ scheduled-python-3.7:
   image: bilbydev/bilby-test-suite-python37
   only:
     - schedules
-  before_script:
-    # Install the dependencies specified in the Pipfile
-    - pipenv install --three --python=/opt/conda/bin/python --system --deploy
   script:
     - python setup.py install
 
-    # Run pyflakes
-    - flake8 .
-
-    # Run tests
-    - pytest
-
     # Run tests which are only done on schedule
     - pytest test/example_test.py
     - pytest test/gw_example_test.py