Refactor container_start_test.go to use Tigron

Updates tests to use nerdtest.Setup and the Tigron testing framework
as per issue containerd #4613.

Signed-off-by: Nuwed Munshi <nuwed.munshi@gmail.com>

Author: munshinuwed

cmd/nerdctl/container/container_start_test.go

@@ -20,10 +20,11 @@ import (
 	"runtime"
 	"testing"
 
-	"github.com/containerd/nerdctl/v2/pkg/testutil"
-	"github.com/containerd/nerdctl/pkg/testutil/nerdtest"
 	"github.com/containerd/nerdctl/mod/tigron/expect"
 	"github.com/containerd/nerdctl/mod/tigron/test"
+
+	"github.com/containerd/nerdctl/v2/pkg/testutil"
+	"github.com/containerd/nerdctl/v2/pkg/testutil/nerdtest"
 )
 
 func TestStart(t *testing.T) {