1. Slice of fix for Bug#42003 tests missing the disconnect of connections <> default

- If missing: add "disconnect <session>"
   - If physical disconnect of non "default" sessions is not finished
     at test end: add routine which waits till this happened
+ additional improvements like
  - remove superfluous files created by the test
  - replace error numbers by error names
  - remove trailing spaces, replace tabs by spaces
  - unify writing of bugs within comments
  - correct comments
  - minor changes of formatting
Modifications according to the code review are included.
Fixed tests:
grant2
grant3
lock_tables_lost_commit
mysqldump
openssl_1
outfile

mysql-test/r/lock_tables_lost_commit.result

@@ -1,8 +1,8 @@
-drop table if exists t1;
-create table t1(a int) engine=innodb;
-lock tables t1 write;
-insert into t1 values(10);
-select * from t1;
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1(a INT) ENGINE=innodb;
+LOCK TABLES t1 WRITE;
+INSERT INTO t1 VALUES(10);
+SELECT * FROM t1;
 a
 10
-drop table t1;
+DROP TABLE t1;