Add the cleanup by dropping the database 'track' in test "rpl_bug31076".


mysql-test/suite/rpl/r/rpl_bug31076.result:
  Fix bug#31150 "Test case does not cleanup":
  Drop the database 'track' which was newly created for this test.
mysql-test/suite/rpl/t/rpl_bug31076.test:
  Fix bug#31150 "Test case does not cleanup":
  Drop the database 'track' which was newly created for this test.