Tasks from previous route instance should not be displayed in the Past tasks view

When a user starts a second workflow on a document, the steps of the first workflow are displayed in the Previous tasks, although they were done on another workflow.

Steps to reproduce:

1. On a document, start a review with user 1.
2. Start the review.
3. Abandon the workflow with Administrator (the initiator cannot abandon it, see NXP-10004).
4. With user 1, start a workflow on the same document.
   -> The "Choose participants" task of the previous workflow is displayed in the Previous tasks (you may need to refresh).
   Only the tasks of the current workflow should be displayed there.