Test: Fix process leaks when retrying scenario tests (#6863)

https://github.com/XTLS/Xray-core/pull/6863#pullrequestreview-5362117967

testing/scenarios/dokodemo_test.go

@@ -115,6 +115,9 @@ func TestDokodemoTCP(t *testing.T) {
 			defer CloseServer(server)
 			break
 		}
+		if server != nil {
+			CloseServer(server)
+		}
 		retry++
 		if retry > 5 {
 			t.Fatal("All attempts failed to start client")
@@ -209,6 +212,9 @@ func TestDokodemoUDP(t *testing.T) {
 			defer CloseServer(server)
 			break
 		}
+		if server != nil {
+			CloseServer(server)
+		}
 		retry++
 		if retry > 5 {
 			t.Fatal("All attempts failed to start client")

testing/scenarios/socks_test.go

@@ -227,6 +227,9 @@ func TestSocksBridageUDP(t *testing.T) {
 			defer CloseServer(server)
 			break
 		}
+		if server != nil {
+			CloseServer(server)
+		}
 		retry++
 		if retry > 5 {
 			t.Fatal("All attempts failed to start server")
@@ -342,6 +345,9 @@ func TestSocksBridageUDPWithRouting(t *testing.T) {
 			defer CloseServer(server)
 			break
 		}
+		if server != nil {
+			CloseServer(server)
+		}
 		retry++
 		if retry > 5 {
 			t.Fatal("All attempts failed to start server")