bug#64876: 30.0.50; byte-compiler warning

[Richard Copley]

Evaluating the form "(byte-compile '(= (point)))" gives the
warning "reference to free variable ‘form’", starting from this
commit:

  e55855c5a1e85e230d2860c973358a34eb72da64
  Commit:     Mattias Engdegård <mattiase@acm.org>
  CommitDate: Sun Jan 29 12:02:57 2023 +0100
  Better compilation of n-ary comparisons

Is there a missing comma in "`(progn (cadr form) t))" in
byte-opt--nary-comparison in the case of 1 argument?

In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, cairo version
 1.16.0) of 2023-07-26 built on machine
Repository revision: 04a930a08ce80d8dcc123f86a3f153f23ec31a29
Repository branch: master
System Description: Ubuntu 22.04.1 LTS

Configured using:
 'configure --with-x-toolkit=no --with-xpm=ifavailable
 --with-jpeg=ifavailable --with-gif=ifavailable --with-tiff=ifavailable'

Configured features:
CAIRO FREETYPE GLIB GMP GNUTLS GPM GSETTINGS JSON LIBSELINUX LIBXML2
MODULES NOTIFY INOTIFY OLDXMENU PDUMPER PNG SECCOMP SOUND SQLITE3
THREADS X11 XDBE XIM ZLIB

Important settings:
  value of $LANG: C.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  blink-cursor-mode: t
  buffer-read-only: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
epg-config gnus-util text-property-search time-date subr-x mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
cl-loaddefs cl-lib sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils term/xterm xterm byte-opt gv bytecomp byte-compile
rmc iso-transl tooltip cconv eldoc paren electric uniquify ediff-hook
vc-hooks lisp-float-type elisp-mode mwheel term/x-win x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode lisp-mode prog-mode register
page tab-bar menu-bar rfn-eshadow isearch easymenu timer select
scroll-bar mouse jit-lock font-lock syntax font-core term/tty-colors
frame minibuffer nadvice seq simple cl-generic indonesian philippine
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese composite emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help abbrev obarray oclosure
cl-preloaded button loaddefs theme-loaddefs faces cus-face macroexp
files window text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget keymap hashtable-print-readable backquote
threads inotify dynamic-setting system-font-setting font-render-setting
cairo x multi-tty move-toolbar make-network-process emacs)

Memory information:
((conses 16 47432 9576) (symbols 48 5869 0) (strings 32 14970 1832)
 (string-bytes 1 423597) (vectors 16 8368)
 (vector-slots 8 105904 7199) (floats 8 24 9048) (intervals 56 256 5)
 (buffers 976 11))