bug#36566: 27.0.50; debug is sometimes horribly slow

[Stefan Monnier]

> Don't have time for more today, but I think this has promise.  And this
> means that we can introduce more printer settings without introducing
> more global dynamic variables.

Not sure how to do it for `cl-print`, tho.  I suspect we'll end up
having to use dynamic vars internally otherwise it'll break the existing
signature of `cl-print-object` (we can't so easily add an optional arg
to a generic function).


        Stefan