Advanced sector commitment tests

[ZenGround0]

There are several sector commitment scenarios that still require testing. Most of these involve more complex interactions than are currently being tested, both between different areas of miner actor logic or across actors. Some of these are good candidates for the upcoming inter-actor scenario testing framework. These were partially gathered from an untracked TODO in TestCommitments

1. Concurrent attempts to upgrade the same CC sector -- one upgrade attempt should succeed.
2. Insufficient funds for prove commit -- gas is charged while reporting to power actor so need scenario testing
3. Invalid seal proofs -- checked during power actor cron tick so need scenario testing
4. CC sector targeted for upgrade expires naturally before the upgrade is proven
5. Sufficient funds to cover pre commit of new sector but insufficient funds to cover the IP of CC sector we are upgrading from results in ErrInsufficientFunds (PCD is max of old sector IP and calculated PCD)