TransactionState.FromStackItem throws when state not available

[devhawk]

#2591 was the first PR merged after Neo 3.1 shipped. This PR added a public VMState State; field to TransactionState. However, the TransactionState.FromStackItem method does not take into account that the State field will not be present for any transactions that were recorded before 3.2 ships. So any 3.2 code that attempts to retrieve a TransactionState that was recorded during 3.1 or earlier will throw.

This will affect any method that calls LedgerContract.GetTransactionState

[devhawk]

Note, this is likely NOT an issue if we do a full resync for 3.2 (which may be required for other reasons). However, the existing error message (index out of range) is not going to be helpful for an operator who runs into this issue.

[shargon]

I think that we should resync