bug#65051: internal_equal manipulates symbols with position without checking symbols-with-pos-enabled.

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: acm@muc.de,  65051@debbugs.gnu.org
> Date: Sat, 12 Aug 2023 14:46:24 -0400
> 
> +A @dfn{symbol with position} is a pair of a symbol, the @dfn{bare
> +symbol}, together with an unsigned integer called the @dfn{position}.
> +Symbol with position cannot themselves have entries in obarrays
   ^^^^^^
"Symbols"