Adaot file-notify-tests.el test cases

Adaot file-notify-tests.el test cases

* lisp/filenotify.el (file-notify-rm-watch): Ignore `file-notify-error'.

* src/inotify.c (Finotify_valid_p): Adapt docstring.

* test/automated/file-notify-tests.el ()
(file-notify-test03-autorevert)
(file-notify-test04-file-validity)
(file-notify-test04-file-validity-remote)
(file-notify-test05-dir-validity)
(file-notify-test05-dir-validity-remote): Adapt docstring.
(file-notify-test04-file-validity): Let events arrive before
calling final `file-notify-valid-p'.  Do not ignore errors.
(file-notify-test05-dir-validity): Do not manipulate
`temporary-file-directory', it isn't necessary.  Let events arrive
before calling final `file-notify-valid-p'.  Do not ignore errors.