bug#63757: 29.0.91 order of package paths changed: random old versions of packages in load-path

[Stefan Monnier]

> So what exactly was the change installed back in Aug 2022 supposed to
> improve?

I believe its intention was only to give preference to the VC packages
(I still don't know why it moved the "prefer built-in packages" part
(and then changed it to test `package-disabled-p`); I presume it was an
accident).

So my patch *may* be a regression for users of `package-vc`, but since
it's a new feature in Emacs-29, I think it's perfectly acceptable.
Especially because the sort it implemented is wrong (because the sort
predicate fails to define a partial order, so the output will depend on
arbitrary details of how `sort` happens to pass elements to the
predicate), so it's not at all clear that it does what it intends to
do anyway.
Furthermore I believe that it is mostly redundant: VC packages should
almost always already be sorted first by virtue of the version being
almost always higher than non-VC packages.


        Stefan