MDEV-13255 main.status failed in buildbot

Test fails sporadically and very rarely on this:
```
let $org_queries= `SHOW STATUS LIKE 'Queries'`;
SELECT f1();
CALL p1();
let $new_queries= `SHOW STATUS LIKE 'Queries'`;
let $diff= `SELECT SUBSTRING('$new_queries',9)-SUBSTRING('$org_queries',9)`;
```
if COM_QUIT from one of the earlier (in the test) disconnect's
happens between the two SHOW STATUS commands.
Because COM_QUIT increments "Queries".

The directly previous test uses wait_condition to wait for
its disconnects to complete. But there are more disconnects earlier
in the test file and nothing waits for them.

Let's change wait_condition to wait for *all* disconnect to complete.

mysql-test/main/status.test

@@ -280,7 +280,6 @@ show status like 'Com%function';
 #
 connect (root, localhost, root,,test);
 connection root;
-let $root_connection_id= `select connection_id()`;
 --disable_warnings
 create database db37908;
 --enable_warnings
@@ -296,7 +295,6 @@ delimiter ;|
 
 connect (user1,localhost,mysqltest_1,,test);
 connection user1;
-let $user1_connection_id= `select connection_id()`;
 
 --error ER_TABLEACCESS_DENIED_ERROR
 select * from db37908.t1;
@@ -315,11 +313,8 @@ drop procedure proc37908;
 drop function func37908;
 REVOKE ALL PRIVILEGES, GRANT OPTION FROM mysqltest_1@localhost;
 DROP USER mysqltest_1@localhost;
-# Wait till the sessions user1 and root are disconnected
-let $wait_condition =
-  SELECT COUNT(*) = 0
-  FROM information_schema.processlist
-  WHERE  id in ('$root_connection_id','$user1_connection_id');
+# Wait until all non-default sessions are disconnected
+let $wait_condition = SELECT COUNT(*) = 1 FROM information_schema.processlist;
 --source include/wait_condition.inc
 
 #