Call file notification actions properly in filenotify-tests.el

Call file notification actions properly in filenotify-tests.el

* test/lisp/filenotify-tests.el (file-notify--test-wait-for-events):
Rename from `file-notify--wait-for-events'.  Adapt all callees.
(file-notify--test-cleanup): Reset also `file-notify--test-event'
and `file-notify--test-file nil'.
(file-notify--test-event-desc, file-notify--test-event-action):
New accessor functions.
(file-notify-test02-rm-watch, file-notify--test-event-test)
(file-notify--test-with-actions-check)
(file-notify--test-with-actions-explainer): Use them.
(file-notify--test-with-actions-check)
(file-notify--test-with-actions-explainer)
(file-notify--test-with-actions): Rename them from *-events-*.
Rename also internal variables accordingly.  Adapt all callees.