MDEV-8211 plugins.server_audit fails sporadically in buildbot.

   More fixes to assure the order of queries in the log.

mysql-test/suite/plugins/t/server_audit.test

@@ -50,6 +50,7 @@ show variables like 'server_audit%';
 set global server_audit_mode=1;
 set global server_audit_events='';
 create database sa_db;
+--sleep 2
 connect (con1,localhost,root,,test);
 connection con1;
 --sleep 2

mysql-test/suite/plugins/t/thread_pool_server_audit.test

@@ -50,6 +50,7 @@ show variables like 'server_audit%';
 set global server_audit_mode=1;
 set global server_audit_events='';
 create database sa_db;
+--sleep 2
 connect (con1,localhost,root,,test);
 connection con1;
 --sleep 2