add "libnm_async_activation_cancellable_no_crash" test
Created by: fpokryvk
use reproducer from Gris Ge https://bugzilla.redhat.com/show_bug.cgi?id=1642625#c11
https://bugzilla.redhat.com/show_bug.cgi?id=1643085
FIX: nmcli_monitor_assertion_con_up_down uses eth2 instead of eth8
@Build:nm-1-14