Bugfix: ensure consistency of m_failed_blocks after reconsiderblock
Bugfix: ensure consistency of m_failed_blocks after reconsiderblock

Github-Pull: #13199
Rebased-From: 11fa6bb66e8c1562305d034903a0dc6aee6eea20

viacoin/viacoin,starwels/starwels,myriadteam/myriadcoin,viacoin/viacoin,DigitalPandacoin/pandacoin,GroestlCoin/bitcoin,myriadteam/myriadcoin,peercoin/peercoin,myriadcoin/myriadcoin,GroestlCoin/bitcoin,gjhiggins/vcoincore,starwels/starwels,gjhiggins/vcoincore,myriadteam/myriadcoin,GroestlCoin/GroestlCoin,gjhiggins/vcoincore,1185/starwels,DigitalPandacoin/pandacoin,ppcoin/ppcoin,1185/starwels,starwels/starwels,myriadcoin/myriadcoin,GroestlCoin/GroestlCoin,GroestlCoin/GroestlCoin,myriadteam/myriadcoin,viacoin/viacoin,DigitalPandacoin/pandacoin,peercoin/peercoin,GroestlCoin/bitcoin,DigitalPandacoin/pandacoin,starwels/starwels,peercoin/peercoin,starwels/starwels,starwels/starwels,myriadcoin/myriadcoin,gjhiggins/vcoincore,myriadcoin/myriadcoin,1185/starwels,DigitalPandacoin/pandacoin,viacoin/viacoin,myriadteam/myriadcoin,GroestlCoin/GroestlCoin,viacoin/viacoin,ppcoin/ppcoin,myriadcoin/myriadcoin,myriadcoin/myriadcoin,peercoin/peercoin,GroestlCoin/GroestlCoin,myriadteam/myriadcoin,gjhiggins/vcoincore,GroestlCoin/GroestlCoin,1185/starwels,DigitalPandacoin/pandacoin,ppcoin/ppcoin,peercoin/peercoin,1185/starwels,GroestlCoin/bitcoin,peercoin/peercoin,GroestlCoin/bitcoin,gjhiggins/vcoincore,ppcoin/ppcoin,1185/starwels,viacoin/viacoin,GroestlCoin/bitcoin