[Multisend][Wallet] Don't send multiple multisend transactions for a stake that resulted …

[CryptoDev-Project]

…in a UTXO split

At the moment, where the UTXO that wins a staking reward is split, the subsequent multi-send transaction sends the value of the staking reward multiple times - once per split output.

[CryptoDev-Project]

Of course, a slightly more complex solution involving splitting the value of the staking reward over each output could be put in place - but I don't believe that offers any advantage to the user, adds to chain bloat and unnecessary additional fees would be incurred by the recipient of the staking reward.

[CaveSpectre11]

I know this is from the existing code and not the changed code; but the !sendMSonMNReward I believe is unnecessary; as sendMSonMNReward will only be true if the output is a masternode reward, which would mean that ut.tx->IsCoinStake() will be false. So if the setting of sendMSOnStake finds "IsCoinStake() to be true, !sendNSonMNReward will always be true; so it has no effect on the logic.

[CryptoDev-Project]

@CaveSpectre11 , my understanding is that IsCoinStake is at transaction level and the masternode reward is merely an additional output to the coin stake transaction.

Therefore, I believe it to be the case that IsCoinStake, which merely checks that there is more than one transaction output, the first of which must be empty, can be true whilst the coins themselves are actually sourced from the masternode reward.

[CryptoDev-Project]

Closing this PR with minor fix as #1096 offers a much more complete solution, especially now that stake splitting can result in many, as opposed to just two, outputs.