underfill: port near-empty-template guard to DGB, BTC, BCH (+ KATs)#728

frstrtr merged 2 commits into

masterfrstrtr/c2pool:masterfrom

fix/underfill-guard-dgb-btc-bchfrstrtr/c2pool:fix/underfill-guard-dgb-btc-bchCopy head branch name to clipboard