Clean Docker between CICD runs

[msmith-techempower]

Error: No space left on device : '/home/runner/runners/2.323.0/_diag/pages/973011ad-f1a5-4644-97d6-585886b34af6_a285525a-2d47-4a5e-8dc3-09ed5f794c4c_1.log'

Happening with some regularity for languages with many many permutations (CSharp, I'm looking at you).

We should probably clean up Docker images and whatnot before a verification run of a framework. This will definitely increase the time it takes to run in CICD, but also it will mean that the full test run will succeed more often.

@NateBrady23 What do you think?