testing: Add tkm xfrmproxy-expire test

This test asserts that the handling of XFRM expire messages from the
kernel are handled correctly by the xfrm-proxy and the Esa Event Service
(EES) in charon-tkm.

testing/tests/tkm/xfrmproxy-expire/posttest.dat

@@ -0,0 +1,5 @@
+moon::DAEMON_NAME=charon-tkm ipsec stop
+moon::killall xfrm_proxy
+moon::killall tkm_keymanager
+moon::rm -f /tmp/tkm.rpc.ike /tmp/tkm.rpc.ees /tmp/tkm.log /tmp/xfrm_proxy.log
+sun::ipsec stop