[devtools] fix sorting in ExecutionPlan._check_permissions on python3
Sort lists instead of dict_items objects to get predictable results.
With this change, unittest_querier.UtilsTC.test_preprocess_security
passes every time instead of once in a blue moon. Closes #11759133.
missing-dep-for-interpreter make => make | build-essential | dpkg-dev (usr/*/cubicweb/skeleton/debian/rules.tmpl)