* core/state/snapshot: print warning if failed to resolve journal
* core/state/snapshot: fix snapshot recovery
When we meet the snapshot journal consisted with:
- disk layer generator with new-format
- diff layer journal with old-format
The base layer should be returned without error.
The broken diff layer can be reconstructed later
but we definitely don't want to reconstruct the
huge diff layer.
* core: add tests
e6402677c2