(nxml-with-invisible-motion): Delete macro.

(nxml-with-invisible-motion): Delete macro.

Don't use this macro any more since it doesn't do anything since Emacs-25
changed the default of `inhibit-point-motion-hooks` to t.

* lisp/nxml/nxml-util.el (nxml-with-invisible-motion): Delete macro.
* lisp/nxml/nxml-mode.el (nxml-mode, nxml-cleanup):
* lisp/nxml/rng-valid.el (rng-do-some-validation):
* lisp/nxml/rng-nxml.el (rng-set-state-after): Don't use it.