zdtm/lock: add futex_add_and_wake and futex_wait_while_lt

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
zdtm/maps007: remove spinlocks from the test

Use futex for synchronization instead of spinning on atomic variables.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>