MDEV-38471 - funcs_1.processlist_val_no_prot fails sporadically

Test output was affected by incompletely closed preceding connections.

Wait for connections to leave I_S.PROCESSLIST before issuing
SHOW PROCESSLIST.

Also fixes similar failures in funcs_1.processlist_val_ps.

Author: svoj

mysql-test/suite/funcs_1/datadict/processlist_val.inc

@@ -54,6 +54,8 @@
 ################################################################################
 
 # Basic preparations
+let $count_sessions= 1;
+source include/wait_until_count_sessions.inc;
 --error 0, ER_CANNOT_USER
 DROP USER test_user@'localhost';
 CREATE USER test_user@'localhost';