Refactor functional coverage

[jordancarlin]

• Updates to testbench, simulation scripts, and config files for compatibility with the overhauled functional coverage in cvw-arch-verif.
• Functional coverage and lockstep are now two discrete flags for wsim.

[jordancarlin]

This should finally be ready to go! The one thing we still need to decide is if we want regression-wally --fcov to just run functional coverage or to run functional coverage and lockstep simultaneously. wsim will definitely have separate flags, but we could go either way for regression-wally.

[davidharrishmc]

I think --fcov should do functional coverage and lockstep, because that's the use case we generally care about at this point.