Test Reframing

[rslawson]

So currently, reframing goes completely unused in any of our HITL tests. I attempted to enable it in my rs/swCcTopologiesTest-rfen branch, but for various reasons I stopped work on that for the time being. Furthermore, whether reframing is enabled is configured on the Clash side of things and passed through to the software by way of an MMIO register, but this should probably be done by some other mechanism.

As for why I stopped work on reframing testing, there's a couple reasons.

1. There's not a good way currently to ensure that reframing begins at the same time across all nodes in the test. Maybe there's a case to be made for using a constant offset from the start of the test, but this would only work within the context of the topology tests where we can make assumptions about an upper bound for stabilisation.
2. For some reason, the Rust code doesn't actually seem to affect the clock offsets? As far as I can tell the reframing enable is getting passed through to the Rust code, but it's never actually doing anything with it.