Lazy migration requires both dumped and restored processes to coexist at
the same time. This breaks some basic assumptions in the zdtm design.
Simulation of lazy migration with the page server allows testing most of
the involved code paths without major intervention into zdtm
infrastructure.

travis-ci: success for lazy-pages: improve testability (rev2)
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>