mock e2e test: reduce flakiness by not testing all calls

kubelet sometimes calls NodeStageVolume an NodePublishVolume too
often, which breaks this test and leads to flakiness. The test isn't
about that, so we can relax the checking and it still covers what it
was meant to cover.

test/e2e/storage/csi_mock_volume.go

@@ -772,17 +772,23 @@ var _ = utils.SIGDescribe("CSI mock volume", func() {
 
 		createVolume := "CreateVolume"
 		deleteVolume := "DeleteVolume"
-		publishVolume := "NodePublishVolume"
+		// publishVolume := "NodePublishVolume"
 		unpublishVolume := "NodeUnpublishVolume"
-		stageVolume := "NodeStageVolume"
+		// stageVolume := "NodeStageVolume"
 		unstageVolume := "NodeUnstageVolume"
 
 		// These calls are assumed to occur in this order for
-		// each test run.
+		// each test run. NodeStageVolume and
+		// NodePublishVolume should also be deterministic and
+		// only get called once, but sometimes kubelet calls
+		// both multiple times, which breaks this test
+		// (https://github.com/kubernetes/kubernetes/issues/90250).
+		// Therefore they are temporarily commented out until
+		// that issue is resolved.
 		deterministicCalls := []string{
 			createVolume,
-			stageVolume,
-			publishVolume,
+			// stageVolume,
+			// publishVolume,
 			unpublishVolume,
 			unstageVolume,
 			deleteVolume,
@@ -796,8 +802,9 @@ var _ = utils.SIGDescribe("CSI mock volume", func() {
 					lateBinding:    test.lateBinding,
 					enableTopology: test.topology,
 
-					// Not strictly necessary, but without it, the external-attacher takes two minutes to detach
-					// the volume?! Looks like a bug.
+					// Not strictly necessary, but runs a bit faster this way
+					// and for a while there also was a problem with a two minuted delay
+					// due to a bug (https://github.com/kubernetes-csi/csi-test/pull/250).
 					disableAttach:  true,
 					registerDriver: true,
 				}