test: fix secondary chains acceptance coinstake selection on forks inconsistencies.
test: fix secondary chains acceptance coinstake selection on forks inconsistencies.

As the wallet is not prepared to follow several chains at the same time,
need to manually remove from the stakeable utxo set every already used
coinstake inputs on the previous blocks of the parallel chain so they
are not used again.

PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX