DRA E2E node: fix cleanup of tests using separate registrar

8fed05c5b7 fixed the cleanup of tests which start
registrar and service in a single call. But tests which first started the
registrar and then the service separately still had the problem:

- registrar is started with test context
- pods remain running at end of test
- registrar stops because of test context cancellation
- pods remain pending despite deletion because the driver gets
  unregistered (timing dependent, so this may have flaked)

The fix is to also clean up the registrar after the test, in reverse startup
order.

test/e2e_node/dra_test.go

@@ -1056,7 +1056,7 @@ func newRegistrar(ctx context.Context, clientSet kubernetes.Interface, nodeName,
 	allOpts = append(allOpts, opts...)
 
 	registrar, err := testdriver.StartPlugin(
-		ctx,
+		context.WithoutCancel(ctx), // It gets stopped during test cleanup or when requested earlier.
 		cdiDir,
 		driverName,
 		clientSet,
@@ -1065,6 +1065,7 @@ func newRegistrar(ctx context.Context, clientSet kubernetes.Interface, nodeName,
 		allOpts...,
 	)
 	framework.ExpectNoError(err, "start only Kubelet plugin registrar")
+	ginkgo.DeferCleanup(registrar.Stop)
 	return registrar
 }
 
@@ -1159,6 +1160,10 @@ func draServiceCleanup(ctx context.Context, clientSet kubernetes.Interface, driv
 	ginkgo.By("Deleting pods and waiting for ResourceClaims to be released...")
 	framework.ExpectNoError(clientSet.CoreV1().Pods(testNamespace).DeleteCollection(ctx, metav1.DeleteOptions{}, metav1.ListOptions{}))
 
+	// Failing here is a bit more obvious than in the metric check below.
+	// The metrics get checked, too, because we want to be certain that those go down.
+	gomega.Eventually(ctx, framework.ListObjects(clientSet.CoreV1().Pods(testNamespace).List, metav1.ListOptions{})).Should(gomega.HaveField("Items", gomega.BeEmpty()), "All pods should be deleted, shut down and removed.")
+
 	// We allow for a delay because it takes a while till the kubelet fully deals with pod deletion.
 	// Typically there is no dra_resource_claims_in_use entry for the driver (covered by gstruct.IgnoreMissing).
 	// If there is one, it must be zero.