hs-test: experimental support for multiple test instances

- appending PID to interface and container names
- added a check for used IP addresses
- TestEnvoyProxyHttpTcp and TestTcpWithLoss are broken when running multiple instances

Type: test

Change-Id: Ib917079ec7cf851dee59ff9c67e74f48c7c5e3c6
Signed-off-by: adrianvillin <avillin@cisco.com>
diff --git a/extras/hs-test/ldp_test.go b/extras/hs-test/ldp_test.go
index 1ccf859..8d9168d 100644
--- a/extras/hs-test/ldp_test.go
+++ b/extras/hs-test/ldp_test.go
@@ -62,7 +62,7 @@
 	s.log("attaching client to vpp")
 	var clnRes = make(chan string, 1)
 	clnEnv := append(os.Environ(), ldpreload, "VCL_CONFIG="+clientVclFileName)
-	serverVethAddress := s.netInterfaces[serverInterfaceName].ip4AddressString()
+	serverVethAddress := s.getInterfaceByName(serverInterfaceName).ip4AddressString()
 	go s.startClientApp(serverVethAddress, clnEnv, clnCh, clnRes)
 	s.log(<-clnRes)