tests: Add KnapsackGroupOutputs helper function
tests: Add KnapsackGroupOutputs helper function

In order to change the KnapsackSolver tests to call KnapsackSolver, we
need KnapsackGroupOutputs to create the OutputGroups filtered with the
filter criteria.

ajtowns/bitcoin,lateminer/bitcoin,jamesob/bitcoin,domob1812/bitcoin,namecoin/namecoin-core,GroestlCoin/bitcoin,mm-s/bitcoin,mm-s/bitcoin,sipsorcery/bitcoin,GroestlCoin/bitcoin,GroestlCoin/bitcoin,bitcoinsSG/bitcoin,kallewoof/bitcoin,kallewoof/bitcoin,domob1812/namecore,yenliangl/bitcoin,instagibbs/bitcoin,fanquake/bitcoin,anditto/bitcoin,andreaskern/bitcoin,yenliangl/bitcoin,andreaskern/bitcoin,yenliangl/bitcoin,yenliangl/bitcoin,anditto/bitcoin,GroestlCoin/bitcoin,MarcoFalke/bitcoin,fujicoin/fujicoin,domob1812/namecore,jlopp/statoshi,bitcoin/bitcoin,bitcoinsSG/bitcoin,namecoin/namecoin-core,Xekyo/bitcoin,sipsorcery/bitcoin,prusnak/bitcoin,namecoin/namecore,kallewoof/bitcoin,instagibbs/bitcoin,tecnovert/particl-core,instagibbs/bitcoin,GroestlCoin/GroestlCoin,particl/particl-core,sstone/bitcoin,AkioNak/bitcoin,domob1812/namecore,MarcoFalke/bitcoin,namecoin/namecoin-core,dscotese/bitcoin,GroestlCoin/GroestlCoin,bitcoinsSG/bitcoin,sstone/bitcoin,lateminer/bitcoin,tecnovert/particl-core,AkioNak/bitcoin,domob1812/namecore,bitcoinknots/bitcoin,MarcoFalke/bitcoin,jlopp/statoshi,domob1812/bitcoin,sstone/bitcoin,particl/particl-core,mruddy/bitcoin,particl/particl-core,bitcoinsSG/bitcoin,mm-s/bitcoin,Xekyo/bitcoin,particl/particl-core,fanquake/bitcoin,fanquake/bitcoin,jamesob/bitcoin,instagibbs/bitcoin,achow101/bitcoin,mruddy/bitcoin,pataquets/namecoin-core,lateminer/bitcoin,mm-s/bitcoin,kallewoof/bitcoin,bitcoinknots/bitcoin,namecoin/namecore,sstone/bitcoin,fanquake/bitcoin,namecoin/namecore,achow101/bitcoin,MarcoFalke/bitcoin,mruddy/bitcoin,achow101/bitcoin,jambolo/bitcoin,namecoin/namecore,mruddy/bitcoin,jamesob/bitcoin,AkioNak/bitcoin,anditto/bitcoin,particl/particl-core,jambolo/bitcoin,achow101/bitcoin,fujicoin/fujicoin,MarcoFalke/bitcoin,pataquets/namecoin-core,sipsorcery/bitcoin,yenliangl/bitcoin,yenliangl/bitcoin,bitcoin/bitcoin,ajtowns/bitcoin,sipsorcery/bitcoin,ajtowns/bitcoin,prusnak/bitcoin,MarcoFalke/bitcoin,sstone/bitcoin,Xekyo/bitcoin,namecoin/namecoin-core,kallewoof/bitcoin,domob1812/namecore,GroestlCoin/GroestlCoin,domob1812/namecore,sipsorcery/bitcoin,instagibbs/bitcoin,anditto/bitcoin,achow101/bitcoin,prusnak/bitcoin,fujicoin/fujicoin,bitcoinknots/bitcoin,tecnovert/particl-core,namecoin/namecoin-core,Xekyo/bitcoin,dscotese/bitcoin,domob1812/bitcoin,pataquets/namecoin-core,namecoin/namecore,lateminer/bitcoin,Xekyo/bitcoin,pataquets/namecoin-core,AkioNak/bitcoin,Xekyo/bitcoin,fujicoin/fujicoin,sipsorcery/bitcoin,GroestlCoin/bitcoin,ajtowns/bitcoin,jlopp/statoshi,tecnovert/particl-core,bitcoinsSG/bitcoin,bitcoin/bitcoin,prusnak/bitcoin,bitcoin/bitcoin,pataquets/namecoin-core,pataquets/namecoin-core,dscotese/bitcoin,bitcoinknots/bitcoin,namecoin/namecore,tecnovert/particl-core,anditto/bitcoin,lateminer/bitcoin,GroestlCoin/GroestlCoin,fujicoin/fujicoin,GroestlCoin/bitcoin,tecnovert/particl-core,prusnak/bitcoin,jambolo/bitcoin,dscotese/bitcoin,jambolo/bitcoin,achow101/bitcoin,dscotese/bitcoin,sstone/bitcoin,AkioNak/bitcoin,jamesob/bitcoin,lateminer/bitcoin,andreaskern/bitcoin,mruddy/bitcoin,prusnak/bitcoin,fanquake/bitcoin,andreaskern/bitcoin,jamesob/bitcoin,mm-s/bitcoin,bitcoinknots/bitcoin,andreaskern/bitcoin,jlopp/statoshi,bitcoin/bitcoin,namecoin/namecoin-core,mruddy/bitcoin,jambolo/bitcoin,fujicoin/fujicoin,kallewoof/bitcoin,andreaskern/bitcoin,particl/particl-core,domob1812/bitcoin,jlopp/statoshi,GroestlCoin/GroestlCoin,GroestlCoin/GroestlCoin,ajtowns/bitcoin,bitcoin/bitcoin,domob1812/bitcoin,fanquake/bitcoin,jlopp/statoshi,mm-s/bitcoin,domob1812/bitcoin,instagibbs/bitcoin,anditto/bitcoin,dscotese/bitcoin,bitcoinsSG/bitcoin,jamesob/bitcoin,jambolo/bitcoin,AkioNak/bitcoin,ajtowns/bitcoin