abci: use no-op loggers in the examples (#7996)

This averts a rare but annoying log-after-test race condition.

abci/example/example_test.go

@@ -31,18 +31,18 @@ func init() {
 func TestKVStore(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	logger := log.NewTestingLogger(t)
+	logger := log.NewNopLogger()
 
-	logger.Info("### Testing KVStore")
+	t.Log("### Testing KVStore")
 	testBulk(ctx, t, logger, kvstore.NewApplication())
 }
 
 func TestBaseApp(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	logger := log.NewTestingLogger(t)
+	logger := log.NewNopLogger()
 
-	logger.Info("### Testing BaseApp")
+	t.Log("### Testing BaseApp")
 	testBulk(ctx, t, logger, types.NewBaseApplication())
 }
 
@@ -50,9 +50,9 @@ func TestGRPC(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	logger := log.NewTestingLogger(t)
+	logger := log.NewNopLogger()
 
-	logger.Info("### Testing GRPC")
+	t.Log("### Testing GRPC")
 	testGRPCSync(ctx, t, logger, types.NewGRPCApplication(types.NewBaseApplication()))
 }