fix flaky TestStopperMultipleStopees
fix flaky TestStopperMultipleStopees

no-brainer which fixes #3735.

glycerine/cockroach,nieyy/cockroach,sunya123/cockroach,cuongdo/cockroach,vivekmenezes/cockroach,arjun4084346/cockroach,veteranlu/cockroach,marcuswestin/cockroach,vivekmenezes/cockroach,bg451/cockroach,cockroachdb/cockroach,paperstreet/cockroach,vivekmenezes/cockroach,nieyy/cockroach,maxlang/cockroach,petermattis/cockroach,paperstreet/cockroach,maxlang/cockroach,bg451/cockroach,paperstreet/cockroach,arjun4084346/cockroach,glycerine/cockroach,il9ue/cockroach,cockroachdb/cockroach,paperstreet/cockroach,maxlang/cockroach,vivekmenezes/cockroach,sunya123/cockroach,veteranlu/cockroach,cockroachdb/cockroach,marcuswestin/cockroach,paperstreet/cockroach,bg451/cockroach,nieyy/cockroach,cockroachdb/cockroach,glycerine/cockroach,nieyy/cockroach,cockroachdb/cockroach,cockroachdb/cockroach,sunya123/cockroach,vivekmenezes/cockroach,sunya123/cockroach,bg451/cockroach,arjun4084346/cockroach,glycerine/cockroach,sunya123/cockroach,vaibhavarora/cockroach,marcuswestin/cockroach,veteranlu/cockroach,vivekmenezes/cockroach,marcuswestin/cockroach,arjun4084346/cockroach,vaibhavarora/cockroach,petermattis/cockroach,il9ue/cockroach,veteranlu/cockroach,glycerine/cockroach,cockroachdb/cockroach,bg451/cockroach,paperstreet/cockroach,marcuswestin/cockroach,il9ue/cockroach,vaibhavarora/cockroach,petermattis/cockroach,il9ue/cockroach,marcuswestin/cockroach,glycerine/cockroach,vaibhavarora/cockroach,glycerine/cockroach,cockroachdb/cockroach,arjun4084346/cockroach,cuongdo/cockroach,maxlang/cockroach,arjun4084346/cockroach,veteranlu/cockroach,nieyy/cockroach,vivekmenezes/cockroach,paperstreet/cockroach,vaibhavarora/cockroach,vaibhavarora/cockroach,petermattis/cockroach,paperstreet/cockroach,sunya123/cockroach,vaibhavarora/cockroach,cuongdo/cockroach,il9ue/cockroach,veteranlu/cockroach,bg451/cockroach,marcuswestin/cockroach,bg451/cockroach,petermattis/cockroach,marcuswestin/cockroach,cuongdo/cockroach,sunya123/cockroach,vivekmenezes/cockroach,maxlang/cockroach,nieyy/cockroach,il9ue/cockroach,sunya123/cockroach,petermattis/cockroach,maxlang/cockroach,petermattis/cockroach,petermattis/cockroach,cuongdo/cockroach,arjun4084346/cockroach,nieyy/cockroach,cuongdo/cockroach,veteranlu/cockroach,maxlang/cockroach,nieyy/cockroach,glycerine/cockroach,il9ue/cockroach,cuongdo/cockroach,arjun4084346/cockroach,maxlang/cockroach,vaibhavarora/cockroach,cuongdo/cockroach,il9ue/cockroach,veteranlu/cockroach