Relax the page queue lock assertions in vm_page_remove() and

Relax the page queue lock assertions in vm_page_remove() and
vm_page_free_toq() to account for recent changes that allow
vm_page_free_toq() to be called on some pages without the page queues lock
being held, specifically, pages that are not contained in a vm object and
not a member of a page queue.  (Examples of such pages include page table
pages, pv entry pages, and uma small alloc pages.)