Bug#53102 perfschema.pfs_upgrade fails on sol10 sparc64 max in parallel mode

The reason for the bug above is unclear but
- Modify pfs_upgrade so that it's result is easier to analyze in case something fails
- Fix several minor weaknesses which could cause that a successing test (either an
  already existing or a to be developed one) fails because of imperfect cleanup,
  too slow disconnected sessions etc.
should either fix the bug or reduce it's probability or at least
make the analysis of failures easier.

mysql-test/suite/perfschema/r/query_cache.result

@@ -65,3 +65,4 @@ Variable_name	Value
 Qcache_hits	1
 SET GLOBAL query_cache_size= default;
 drop table t1;
+flush status;

mysql-test/suite/perfschema/r/selects.result

@@ -55,14 +55,21 @@ THREAD_ID	EVENT_ID
 [THREAD_ID]	[EVENT_ID]
 [THREAD_ID]	[EVENT_ID]
 [THREAD_ID]	[EVENT_ID]
+DROP TABLE IF EXISTS t_event;
+DROP EVENT IF EXISTS t_ps_event;
+CREATE TABLE t_event AS
+SELECT EVENT_ID FROM performance_schema.EVENTS_WAITS_CURRENT
+WHERE 1 = 2;
 CREATE EVENT t_ps_event
 ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 SECOND
-DO SELECT DISTINCT EVENT_ID
+DO INSERT INTO t_event
+SELECT DISTINCT EVENT_ID
 FROM performance_schema.EVENTS_WAITS_CURRENT
 JOIN performance_schema.EVENTS_WAITS_HISTORY USING (EVENT_ID)
 ORDER BY EVENT_ID
 LIMIT 1;
 ALTER TABLE t1 ADD COLUMN c INT;
+DROP TRIGGER IF EXISTS t_ps_trigger;
 CREATE TRIGGER t_ps_trigger BEFORE INSERT ON t1
 FOR EACH ROW BEGIN
 SET NEW.c = (SELECT MAX(EVENT_ID)
@@ -76,6 +83,7 @@ id	c
 12	[EVENT_ID]
 13	[EVENT_ID]
 DROP TRIGGER t_ps_trigger;
+DROP PROCEDURE IF EXISTS t_ps_proc;
 CREATE PROCEDURE t_ps_proc(IN tid INT, OUT pid INT)
 BEGIN
 SELECT id FROM performance_schema.PROCESSLIST
@@ -83,6 +91,7 @@ WHERE THREAD_ID = tid INTO pid;
 END;
 |
 CALL t_ps_proc(0, @p_id);
+DROP FUNCTION IF EXISTS t_ps_proc;
 CREATE FUNCTION t_ps_func(tid INT) RETURNS int
 BEGIN
 return (SELECT id FROM performance_schema.PROCESSLIST
@@ -92,6 +101,10 @@ END;
 SELECT t_ps_func(0) = @p_id;
 t_ps_func(0) = @p_id
 1
+SELECT * FROM t_event;
+EVENT_ID
+[EVENT_ID]
 DROP PROCEDURE t_ps_proc;
 DROP FUNCTION t_ps_func;
 DROP TABLE t1;
+DROP TABLE t_event;