test: wait rather than assert presence of file in startupnotify test
test: wait rather than assert presence of file in startupnotify test

Should fix #23967.

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