qa: Stop txindex thread before calling destructor
qa: Stop txindex thread before calling destructor

Github-Pull: #14071
Rebased-From: faf4a9b674186923f8c837e3621d147f504c1944

guncoin/guncoin,vertcoin/vertcoin,Bushstar/UFO-Project,GroestlCoin/GroestlCoin,vmp32k/litecoin,digibyte/digibyte,digibyte/digibyte,lbryio/lbrycrd,BTCGPU/BTCGPU,digibyte/digibyte,gjhiggins/vcoincore,digibyte/digibyte,vmp32k/litecoin,qtumproject/qtum,BTCGPU/BTCGPU,GroestlCoin/bitcoin,Bushstar/UFO-Project,qtumproject/qtum,lbryio/lbrycrd,Bushstar/UFO-Project,GroestlCoin/bitcoin,BTCGPU/BTCGPU,gjhiggins/vcoincore,GroestlCoin/GroestlCoin,GroestlCoin/GroestlCoin,qtumproject/qtum,guncoin/guncoin,qtumproject/qtum,GroestlCoin/GroestlCoin,h4x3rotab/BTCGPU,ahmedbodi/vertcoin,lbryio/lbrycrd,qtumproject/qtum,gjhiggins/vcoincore,guncoin/guncoin,vertcoin/vertcoin,ElementsProject/elements,thrasher-/litecoin,ahmedbodi/vertcoin,GroestlCoin/GroestlCoin,h4x3rotab/BTCGPU,thrasher-/litecoin,digibyte/digibyte,vertcoin/vertcoin,thrasher-/litecoin,ahmedbodi/vertcoin,vmp32k/litecoin,vertcoin/vertcoin,gjhiggins/vcoincore,h4x3rotab/BTCGPU,guncoin/guncoin,ahmedbodi/vertcoin,BTCGPU/BTCGPU,gjhiggins/vcoincore,h4x3rotab/BTCGPU,lbryio/lbrycrd,BTCGPU/BTCGPU,ElementsProject/elements,thrasher-/litecoin,h4x3rotab/BTCGPU,Bushstar/UFO-Project,thrasher-/litecoin,lbryio/lbrycrd,digibyte/digibyte,vmp32k/litecoin,ahmedbodi/vertcoin,vmp32k/litecoin,BTCGPU/BTCGPU,ElementsProject/elements,ElementsProject/elements,Bushstar/UFO-Project,GroestlCoin/bitcoin,h4x3rotab/BTCGPU,guncoin/guncoin,ElementsProject/elements,vmp32k/litecoin,Bushstar/UFO-Project,ElementsProject/elements,thrasher-/litecoin,guncoin/guncoin,qtumproject/qtum,qtumproject/qtum,GroestlCoin/GroestlCoin,vertcoin/vertcoin,ahmedbodi/vertcoin,lbryio/lbrycrd,vertcoin/vertcoin,GroestlCoin/bitcoin,lbryio/lbrycrd,GroestlCoin/bitcoin,gjhiggins/vcoincore,GroestlCoin/bitcoin