Add basic tests for chronik when loading a utxo snapshot. For now we expect that chronik can index the background idb chainstate, and will require a restart to get past the snapshot height.This restarts chronik the same was as other indexers when reaching the snapshot base.
Part of the work to support Chronik with assume was done in D17894:
- not indexing blocks that have `ChainstateRole::ASSUMEDVALID` (blocks arriving on the `m_snapshot_chainstate` while the backroung IBD is still ongoing)
See D17894- selecting the proper chainstate based on the current state
- `m_ibd_chainstate` when an active background IBD is happening
- `m_snapshot_chainstate` after the background IBD is complete
- `m_ibd_chainstate` after a restart when this is the only chainstate left
Add basic tests for chronik when loading a utxo snapshot..