Added a test case for bug #7672.
sql_yacc.yy:
  Fixed bug #7672.
  Made queries of the form (SELECT ...) ORDER BY ... to
  be equivalent to SELECT ... ORDER BY ...


sql/sql_yacc.yy:
  Fixed bug #7672.
  Made queries of the form (SELECT ...) ORDER BY ... to
  be equivalent to SELECT ... ORDER BY ...
mysql-test/t/order_by.test:
  Added a test case for bug #7672.
mysql-test/r/order_by.result:
  Added a test case for bug #7672.