Remove `run_test.py` script.
Remove `run_test.py` script.

As `conda-build` is much better about handling content needed for the
test phase, we no longer need this hacky script to workaround
`conda-build` 1.x's shortcomings. Simply leveraging the features in
`conda-build` 2.x, we should be able to just run the unit tests.

DudLab/rank_filter,jakirkham/rank_filter,DudLab/rank_filter,DudLab/rank_filter,jakirkham/rank_filter,nanshe-org/rank_filter,nanshe-org/rank_filter,nanshe-org/rank_filter,jakirkham/rank_filter