m/test/launch/cluster: print nanoswitch logs

Change-Id: I3a034e075aa253ecb4ef6306e50686a6d44aab80
Reviewed-on: https://review.monogon.dev/c/monogon/+/792
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/test/launch/cluster/cluster.go b/metropolis/test/launch/cluster/cluster.go
index 5c4753d..7b5a211 100644
--- a/metropolis/test/launch/cluster/cluster.go
+++ b/metropolis/test/launch/cluster/cluster.go
@@ -658,6 +658,7 @@
 			InitramfsPath:          "metropolis/test/nanoswitch/initramfs.cpio.lz4",
 			ExtraNetworkInterfaces: switchPorts,
 			PortMap:                portMap,
+			SerialPort:             newPrefixedStdio(99),
 		}); err != nil {
 			if !errors.Is(err, ctxT.Err()) {
 				log.Fatalf("Failed to launch nanoswitch: %v", err)