kubernetes: scheduler: fix API inconsistencies and test compatibility

/kind bug /sig scheduling

There are many APIs which have been excluded in https://github.com/kubernetes/kubernetes/blob/master/pkg/scheduler/algorithmprovider/defaults/compatibility_test.go. For instance, ExtenderConfig is absent (found during https://github.com/kubernetes/kubernetes/issues/65413).

The tests should include all API types to ensure backward compatibility and API consistency.

/cc @liggitt