debug_TraceTransaction does not work

[gballet]

This issue is meant to gather the current state of my investigation into this bug, which is blocking blockscout and other applications from working.

The issue is triggered by the fact that a StateDB is created (from stateAtTransaction/stateAtBlock) which doesn't load the conversion status (e.g. if the conversion has started or ended). As a result, it tries to read data from an empty tree and complains about a 0 nonce.

It should be easy to fix once the conversion status is saved in the database and #316 is fixed, since this might be a similar problem. The fix would be to ensure that LoadTransitionStatus is called from state.New and is initialized from the database.