test: ensure harness nodes are connected before running each test

Due to some of the previous commits, we no longer have persistent
connections to peers whom we have no open channels with. It might be the
case that this is triggered throughout any of the tests, so we'll ensure
that the Alice and Bob harnesses are connected before running each test.

lnd_test.go

@@ -10611,6 +10611,14 @@ func TestLightningNetworkDaemon(t *testing.T) {
 	for _, testCase := range testsCases {
 		logLine := fmt.Sprintf("STARTING ============ %v ============\n",
 			testCase.name)
+
+		err := lndHarness.EnsureConnected(
+			context.Background(), lndHarness.Alice, lndHarness.Bob,
+		)
+		if err != nil {
+			t.Fatalf("unable to connect alice to bob: %v", err)
+		}
+
 		if err := lndHarness.Alice.AddToLog(logLine); err != nil {
 			t.Fatalf("unable to add to log: %v", err)
 		}