sql: fix race in TestPGWireConnectionCloseReleasesLeases
sql: fix race in TestPGWireConnectionCloseReleasesLeases

Fixes #7750

glycerine/cockroach,arjun4084346/cockroach,paperstreet/cockroach,paperstreet/cockroach,sunya123/cockroach,arjun4084346/cockroach,maxlang/cockroach,veteranlu/cockroach,cockroachdb/cockroach,arjun4084346/cockroach,maxlang/cockroach,vivekmenezes/cockroach,paperstreet/cockroach,petermattis/cockroach,vivekmenezes/cockroach,vaibhavarora/cockroach,veteranlu/cockroach,vivekmenezes/cockroach,maxlang/cockroach,vaibhavarora/cockroach,sunya123/cockroach,paperstreet/cockroach,arjun4084346/cockroach,veteranlu/cockroach,vivekmenezes/cockroach,vaibhavarora/cockroach,glycerine/cockroach,cockroachdb/cockroach,petermattis/cockroach,cockroachdb/cockroach,cockroachdb/cockroach,cockroachdb/cockroach,veteranlu/cockroach,arjun4084346/cockroach,glycerine/cockroach,petermattis/cockroach,vivekmenezes/cockroach,maxlang/cockroach,glycerine/cockroach,maxlang/cockroach,vaibhavarora/cockroach,petermattis/cockroach,vivekmenezes/cockroach,glycerine/cockroach,glycerine/cockroach,sunya123/cockroach,maxlang/cockroach,sunya123/cockroach,veteranlu/cockroach,arjun4084346/cockroach,veteranlu/cockroach,vivekmenezes/cockroach,paperstreet/cockroach,glycerine/cockroach,sunya123/cockroach,sunya123/cockroach,veteranlu/cockroach,veteranlu/cockroach,petermattis/cockroach,vaibhavarora/cockroach,vaibhavarora/cockroach,cockroachdb/cockroach,arjun4084346/cockroach,maxlang/cockroach,sunya123/cockroach,vivekmenezes/cockroach,paperstreet/cockroach,cockroachdb/cockroach,cockroachdb/cockroach,petermattis/cockroach,petermattis/cockroach,maxlang/cockroach,glycerine/cockroach,vaibhavarora/cockroach,sunya123/cockroach,vaibhavarora/cockroach,paperstreet/cockroach,petermattis/cockroach,arjun4084346/cockroach,paperstreet/cockroach