- Enable testcases after help from Serg 


client/mysqltest.c:
  Dump output to stdout if no result file is specified
  Don't print verbose_msg when command fails whith expected error
mysql-test/mysql-test-run.pl:
  Don't add all args to the MYSQL_TEST environment variable.
mysql-test/r/mysqltest.result:
  Add test for mysqltest -x
mysql-test/t/mysqltest.test:
  Add test for mysqltest -x