EIEIO: Fix regession (bug#69631)

EIEIO: Fix regession (bug#69631)

Not sure why earlier tests did not catch it, but there are more
places where we bump into problems because `eieio--class-precedence-list`
now returns also non-EIEIO classes.

* lisp/obsolete/eieio-compat.el
(eieio--generic-static-object-generalizer):
* lisp/emacs-lisp/eieio-core.el (eieio--generic-generalizer)
(eieio--generic-subclass-specializers): Handle non-EIEIO parents.

* test/lisp/emacs-lisp/eieio-tests/eieio-test-methodinvoke.el
(eieio-test-method-order-list-7): Adjust test.

(cherry picked from commit 5beb56fb53b2d6ee9d5ad621b7fc2c9d1d0ec9c5)