MDEV-6720 - enable connection log in mysqltest by default

mysql-test/r/empty_user_table.result

@@ -2,6 +2,7 @@ create table t1 as select * from mysql.user;
 truncate table mysql.user;
 flush privileges;
 connect(localhost,u1,,test,MASTER_PORT,MASTER_SOCKET);
+connect  fail,localhost,u1;
 Got one of the listed errors
 insert mysql.user select * from t1;
 drop table t1;