bug#36702: 27.0.50; newline: don't auto-fill regardless of auto-fill-mode

[Andreas Röhler]

Hi,

have an auto-fill-function set in a mode.

When testing, noticed that  this auto-fill-function was called by  
`newline` even if  no auto-fill-mode.

See definition of newline from simple.el, line 22:

(auto-fill-function (if arg nil auto-fill-function))

IMO there is also a docu bug, as this auto-filling is switched of by any arg

whilst docu says: With ARG, insert that many newlines -- which sounds 
unrelated if filling.

Herewith a test-command: inserts "foo" in a temp-buffer by just calling 
newline

(defun auto-fill-test()
  (interactive)
  (let ((auto-fill-function (lambda ()(insert "foo"))))
    (with-temp-buffer
      (switch-to-buffer (current-buffer))
      (newline))))

GNU Emacs 27.0.50 (build 1, i686-pc-linux-gnu, GTK+ Version 3.14.5) of 
2019-06-04