Merge #7971: [qa] Refactor test_framework and pull tester
fad3366 [qa] pull-tester: Adjust comment (MarcoFalke)
fafb33c [qa] Stop other nodes, even when one fails to stop (MarcoFalke)
2222dae [qa] Update README.md (MarcoFalke)
fabbf6b [qa] Refactor test_framework and pull tester (MarcoFalke)