bug#61521: "default" is now the first item returned from (font-faces), breaking various code.

[Gregory Heytings]

> > That comment is obsolete and needs to be changed (and the call to 
> > nreverse should perhaps be removed).
>
> If the order returned by face-list is not guaranteed, then why does it 
> do sorting at all?

Note that the sorting was added recently, in e3b8ddd500.  Before that 
there was no sorting, it just happened that 'default' was the last element 
of that alist.  It's not clear to me why the sorting is there, apparently 
it was added to fix bug#41200.