test: More tests

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
test: Search tests relative to zdtm root dir

This will make it possible to hook in transition
and blocking tests

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
criu: Search CRIU binary in $PATH

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
rpc: Bind listener to INADDR_ANY, not only lo

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>