Jose's patch implementing kind-polymorphic core (09015be8) reverted many of the simplifying changes to interface file TyCon serialization I had made in a previous patch (5d7173f9). Based on the diff I think this was an unintended consequence of how Jose did the merge rather than a real change he intended to make.

In fact, as a result of kind-polymorphic core we don't need to treat the Any TyCon specially any longer so my old simplifying changes can be made even simpler: IfaceTyCon is now just a newtype on IfaceExtName.