Add Cover op support to the JIT

[RobSpringer]

We can just ignore the op, of course, but collecting coverpoint info into some sort of report structure would be neat.

[nanavati]

I think this would go hand-in-hand with adding interpreter side channels for trace outputs.

[cdleary]

Note Ravi added some support in the JIT for side channels for e.g. building/capturing trace outputs, but we don't have coverpoint support in the JIT still and we don't have a pressing need at the moment, so marking as long-term-enhancement until something kicks up the prioritization.