test/e2e: isolate tests into a separate function

Preparation for running the same tests with NodeFeature API enabled
(instead of gRPC).

test/e2e/node_feature_discovery.go

@@ -153,6 +153,7 @@ func cleanupCRDs(cli *nfdclient.Clientset) {
 var _ = SIGDescribe("Node Feature Discovery", func() {
 	f := framework.NewDefaultFramework("node-feature-discovery")
 
+	nfdTestSuite := func(useNodeFeatureApi bool) {
 		Context("when deploying a single nfd-master pod", Ordered, func() {
 			var (
 				masterPod *corev1.Pod
@@ -572,6 +573,13 @@ core:
 				})
 			})
 		})
+	}
+
+	// Run the actual tests
+	Context("when running NFD with gRPC API enabled", func() {
+		nfdTestSuite(false)
+
+	})
 })
 
 // waitForNfdNodeAnnotations waits for node to be annotated as expected.