(cl-deftype): Don't set `cl-deftype-handler` directly

(cl-deftype): Don't set `cl-deftype-handler` directly

In order to make it easier to change that in the future, let
`cl--define-derived-type` take care of storing the derived
type's function into `cl-deftype-handler`.

* lisp/emacs-lisp/cl-preloaded.el (cl--define-derived-type):
Change calling convention.  Set `cl-deftype-handler`.
* lisp/emacs-lisp/cl-macs.el (cl-deftype): Don't set `cl-deftype-handler`,
instead pass the function to `cl--define-derived-type`.

(cherry picked from commit 9f50fdf1e75040d7feaa1edb235377a33da94781)