introduced a new vm_page_write_modified_page().
* Resolved a TODO: vm_page_write_modified_pages() did not mark a to be
written page busy but unlocked its cache which could let someone else
steal that page in the mean time.
* Moved the logic when to move a page to the active or inactive queue to
a new function move_page_to_active_or_inactive_queue().
* Moved page_state_to_string() to vm_page(); it's now also used by the
"page" and "page_queue" KDL commands.
* Made the output of the "page_queue list" command more useful.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22323 a95241bf-73f2-0310-859d-f6bbb57e9c96