test redelegation and storage layout versioning

[snreynolds]

In the case of re-delegating to a new version/upgrading, we have to be careful about storage collisions.

If we want the new version to be able to use the old versions storage then the storage slot calculation cannot change but the changes need to be backwards compatible.

If we want the new version to use new storage we need to migrate the old storage into the new storage layout and change any custom storage slot declarations, by adding a version into the hash.