Simplify orphan processing in preparation for interruptibility
Simplify orphan processing in preparation for interruptibility

Github-Pull: #15644
Rebased-From: 9453018fdc8f02d42832374bcf1d6e3a1df02281

untrustbank/litecoin,GroestlCoin/GroestlCoin,qtumproject/qtum,OmniLayer/omnicore,GroestlCoin/bitcoin,ahmedbodi/vertcoin,vertcoin/vertcoin,myriadteam/myriadcoin,GroestlCoin/bitcoin,myriadteam/myriadcoin,bespike/litecoin,vertcoin/vertcoin,bespike/litecoin,OmniLayer/omnicore,myriadteam/myriadcoin,myriadteam/myriadcoin,GroestlCoin/GroestlCoin,GroestlCoin/bitcoin,OmniLayer/omnicore,qtumproject/qtum,vertcoin/vertcoin,untrustbank/litecoin,myriadcoin/myriadcoin,GroestlCoin/GroestlCoin,GroestlCoin/bitcoin,bespike/litecoin,qtumproject/qtum,myriadteam/myriadcoin,qtumproject/qtum,GroestlCoin/bitcoin,ahmedbodi/vertcoin,vertcoin/vertcoin,qtumproject/qtum,OmniLayer/omnicore,qtumproject/qtum,OmniLayer/omnicore,bespike/litecoin,untrustbank/litecoin,myriadcoin/myriadcoin,vertcoin/vertcoin,myriadteam/myriadcoin,ahmedbodi/vertcoin,GroestlCoin/GroestlCoin,GroestlCoin/GroestlCoin,myriadcoin/myriadcoin,untrustbank/litecoin,untrustbank/litecoin,OmniLayer/omnicore,qtumproject/qtum,GroestlCoin/bitcoin,untrustbank/litecoin,myriadcoin/myriadcoin,ahmedbodi/vertcoin,myriadcoin/myriadcoin,GroestlCoin/GroestlCoin,myriadcoin/myriadcoin,ahmedbodi/vertcoin,bespike/litecoin,ahmedbodi/vertcoin,bespike/litecoin,vertcoin/vertcoin