Write a test that exercises the CalibrateTask in pipe_tasks specifically including exercising CalibrateTask.writeOutputs.

This ticket was motivated by DM-7351 in which processCcd.py failed when writing out calibration information using obs_file because of a call in CalibrateTask.writeOutputs. I don't actually understand why this function ever worked, and I also don't understand how the existing pipe_tasks/tests/testProcessCcd.py, which does use a CalibrateTask didn't trigger a failure.