Clean up logic for deprecated flag --container-runtime in kubelet

Signed-off-by: Ciprian Hacman <ciprian@hakman.dev>

pkg/kubelet/kubelet_test.go

@@ -2355,13 +2355,6 @@ func TestSyncTerminatingPodKillPod(t *testing.T) {
 	checkPodStatus(t, kl, pod, v1.PodFailed)
 }
 
-func TestPreInitRuntimeService(t *testing.T) {
-	err := PreInitRuntimeService(nil, nil, nil, "", "", "", "")
-	if err == nil {
-		t.Fatal("PreInitRuntimeService should fail when not configured with a container runtime")
-	}
-}
-
 func TestSyncLabels(t *testing.T) {
 	tests := []struct {
 		name             string