bug#25215: 25.1.90; js--proper-indentation is affected by the value of forward-sexp-function

[Eli Zaretskii]

> From: Dmitry Gutov <dgutov@webzilla.com>
> Date: Fri, 16 Dec 2016 14:58:35 +0200
> 
> js2-mode derives from js-mode and, starting with Emacs 25.1, inherits
> its indentation function.
> 
> However, forward-sexp-function in js2-mode can be slow because it uses
> the AST, and when the current parsing pass had been interrupted by user
> input, it's forced to finish. Which is slow in large files.
> 
> And its subtleties aren't really needed by the intentation code. So in
> the various bits of code we've brought over from js2-mode we have kept
> the forward-sexp-function->nil binding.
> 
> We've missed it in js--multi-line-declaration-indentation, hovewer. And
> in js--maybe-goto-declaration-keyword-end (though that one only comes
> into play with a non-default value of js-indent-first-init).
> 
> The patch is below.

Thanks, this is okay for the release branch.