Clean tests/functional/data/actual_op/ dir for clear workspace for commit after run arrow_command.sh

Hi,

Sometimes we need run tests/functional/arrow_command.sh after changed some code, to make sure the functions still work fine. Even we had added the path to .gitignore, seems that it only stops committing new files to tests/functional/data/actual_op/, but for the exist files, we can still see the files are modified.

This Pull Request is to clean actual_op dir, to make the workspace more clear.

Regards,
Jun