RAM is not free after deleting a worksheet #7752
Description
Total RAM use does not decrease after deleting a worksheet. In the Trash section, it appears as (running).
I suggest the page is stopped, then deleted, as usually someone deleting a worksheet does not plan on working on it further.
When I have to correct a lot of worksheets from the students, I upload one, correct it, save it, and delete it, but RAM eventually gets collapsed.
CC: @williamstein @sagetrac-acleone @qed777
Component: notebook
Author: Tim Dumol
Reviewer: Alex Leone
Merged: sagenb-0.7
Issue created by migration from https://trac.sagemath.org/ticket/7752