[Consensus] Require standard transactions for testnet
[Consensus] Require standard transactions for testnet

This brings testnet more in-line with the consensus requirements that
are present on mainnet.

PIVX-Project/PIVX,Mrs-X/Darknet,PIVX-Project/PIVX,PIVX-Project/PIVX,Mrs-X/PIVX,Darknet-Crypto/Darknet,benzmuircroft/REWIRE.io,Darknet-Crypto/Darknet,Mrs-X/Darknet,npccoin/npccoin,npccoin/npccoin,Mrs-X/Darknet,benzmuircroft/REWIRE.io,Mrs-X/PIVX,benzmuircroft/REWIRE.io,PIVX-Project/PIVX,Mrs-X/PIVX,Darknet-Crypto/Darknet,Darknet-Crypto/Darknet,PIVX-Project/PIVX,npccoin/npccoin,npccoin/npccoin,Mrs-X/Darknet,npccoin/npccoin,benzmuircroft/REWIRE.io,Mrs-X/PIVX,Darknet-Crypto/Darknet,benzmuircroft/REWIRE.io,benzmuircroft/REWIRE.io,Mrs-X/Darknet,PIVX-Project/PIVX,Mrs-X/PIVX,npccoin/npccoin,PIVX-Project/PIVX,PIVX-Project/PIVX,PIVX-Project/PIVX,Darknet-Crypto/Darknet,Mrs-X/Darknet,Mrs-X/PIVX