criu: mem: skip lazy pages during restore based on pagemap info

Instead of checking whether the VMA containing a page can be lazy for each
page, skip the entire parts of pagemap that have PE_LAZY flag set.

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>