[V129-specific] Tx Coins to not change vault balances when their FromAddress and ToAddress are the same
[V129-specific]
Intended to close #1903 (closed)
'Consolidate (Internal) amounts can be subtracted before being added; for Consolidates, zero flooring (apparent insolvency)'.
Further thoughts:
When there are Migrate memos, hypothetically the observed txin handler could check the ObservedTxOutVoter,
and the observed txout handler could check the ObservedTxInVoter,
whichever is processed later updating both vault balances,
so that the recorded funds transfer always inherently happens simultaneously and the ActiveVault increment never early nor late.
Ideally Migrate supermajority consensus would always happen in the same block due to their MsgObservedTxIn and MsgObservedTxOuts being in the same broadcast transaction,
but it could be reassuring to not have to assume that.
(For instance, what if a node or nodes were to maliciously deliberately leave out one observation while duly observing the other,
resulting in broken-invariant vault balances?)
Please tell me if such a mutually-Voter-checking commit is desired.