We don't need to check that the object is pointer to the GC heap in
vm_ccs_free because it is called during sweeping, which does not free
pages so it can never point to an object that is not on the GC heap.
We don't need to check that the object is pointer to the GC heap in
moved_or_living_object_strictly_p because it is called during reference
updating, which does not free pages so it can never point to an object
that is not on the GC heap.