put at least some output-generating statement in the test

otherwise mysqltest complains "No queries executed but non-empty result file found!"

mysql-test/r/change_user_notembedded.result

@@ -3,3 +3,4 @@ ERROR 28000: Access denied for user 'foo'@'localhost' (using password: NO)
 ERROR 28000: Access denied for user 'foo'@'localhost' (using password: YES)
 ERROR 08S01: Unknown command
 ERROR 08S01: Unknown command
+that's all

mysql-test/t/change_user_notembedded.test

@@ -22,3 +22,5 @@ change_user;
 disconnect test;
 connection default;
 
+--echo that's all
+