Avoid unnecessary loading of subr-x at run-time

Avoid unnecessary loading of subr-x at run-time

* lisp/doc-view.el, lisp/filenotify.el, lisp/info-look.el:
* lisp/svg.el, lisp/emacs-lisp/byte-opt.el, lisp/net/shr.el:
* lisp/textmodes/sgml-mode.el, test/lisp/dom-tests.el:
No need to load subr-x at run-time.
* lisp/gnus/nnheader.el: No need to load subr-x.
; * lisp/emacs-lisp/subr-x.el, lisp/gnus/message.el, lisp/net/nsm.el:
; Comments.