text: Title: Fix flaky Dask test behavior
  Body: There is some flaky behavior with Dask tests, that seem to be related to the tests that use the `cluster_scheduler` fixture. Sometimes these tests do not get run, or do not get reported as being run by codecov, while other times they do.
  
  One test that seems especially problematic is `test_dask_kwargs` in `test_calculate_feature_matrix.py`. 
  
  [Example codecov report](https://app.codecov.io/gh/alteryx/featuretools/compare/2035/changes)
  
  We should investigate the cause of this flaky behavior and fix, as this is causing the codecov project coverage CI check to fail frequently in PR's.