Adding the unit tests for the clean_workspace tool

Created by: prwolfe

As we discussed getting these to always run is vital. I will be working on python 2/3 coexistence next.

@trilinos/framework

Description

Just adding the make spec to get these python tests running.

Motivation and Context

All testing should happen at PR time as well as by hand.

How Has This Been Tested?

Built as if in a PR test and ran the python tests by hand.