CLONE - A teacher can choose whether to allow late assignment submissions

This test requires an assignment with file submissions enabled.

1. Login as a teacher, update the assignment and set a due date in the past. Do not set a cut-off date.
2. Login as a student and upload a file.
3. Check that the file is uploaded successfully and a download link is displayed together with the submission date and time in red (indicating that it is late).
4. Login as a teacher and access the assignment.
5. Follow the 'View/grade all submissions' link and click the Grade link for the late submission
6. Check that the submission displays the due date and a message saying how late it was submitted.