[Stateless SG] Test if TCP packets with various conn state are allowed

In stateless SG there is no connection track so TCP packet of any type
should be allowed by SG. This patch adds test which spawns 2 vms,
connected to 2 different networks and the same router. Both vms are
using different stateless SGs. Finally test asserts that packets of any
of the TCP type (syn, ack, syn-ack, psh, rst, fin) sent from one of the
vms can reach second one.

Change-Id: I23a4b282c83101526af05aa309d578aecaef1fa9
diff --git a/tools/customize_ubuntu_image b/tools/customize_ubuntu_image
index fdd2d12..cb96b17 100755
--- a/tools/customize_ubuntu_image
+++ b/tools/customize_ubuntu_image
@@ -19,6 +19,7 @@
    iperf3
    iputils-ping
    ncat
+   nmap
    psmisc  # provides killall command
    python3
    tcpdump