bug#60659: 30.0.50; tree-sitter: identical nodes are not `equal'

[Eli Zaretskii]

> From: Yuan Fu <casouri@gmail.com>
> Date: Mon, 9 Jan 2023 21:56:19 -0800
> Cc: 60659@debbugs.gnu.org
> 
> Eli, does this look right to you? In particular, I’m not sure if it’s ok to 
> call a lisp function (Ftreesit_node_eq) inside internal_equal, even though it 
> never signals. 

It is better to make a C function from most of the body of
Ftreesit_node_eq, but without the CHECK_NODE parts, and make both
Fequal and Ftreesit_node_eq call that.  Because CHECK_NODE can signal,
right?  Also, you should make sure up front that _both_ o1 and o2 are
treesit nodes, otherwise they cannot be 'equal'.

Lars, Stefan: any comments/suggestions?