Fix for PKI.TestStandby_Operations test to work in ENT (hashicorp#19647)

* Fix for PKI.TestStandby_Operations test to work in ENT

 - Remove wait call to testhelpers.WaitForActiveNodeAndStandbys and
   leverage testhelpers.WaitForStandbyNode instead.

* Use InmemBackendSetup for a proper HA backend in ENT

builtin/logical/pki/backend_test.go

@@ -33,6 +33,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/hashicorp/vault/helper/testhelpers/teststorage"
+
 	"github.com/hashicorp/vault/helper/testhelpers"
 
 	"github.com/hashicorp/vault/sdk/helper/testhelpers/schema"
@@ -6413,13 +6415,12 @@ func TestUserIDsInLeafCerts(t *testing.T) {
 // TestStandby_Operations test proper forwarding for PKI requests from a standby node to the
 // active node within a cluster.
 func TestStandby_Operations(t *testing.T) {
-	conf := &vault.CoreConfig{
+	conf, opts := teststorage.ClusterSetup(&vault.CoreConfig{
 		LogicalBackends: map[string]logical.Factory{
 			"pki": Factory,
 		},
-	}
-	opts := vault.TestClusterOptions{HandlerFunc: vaulthttp.Handler}
-	cluster := vault.NewTestCluster(t, conf, &opts)
+	}, nil, teststorage.InmemBackendSetup)
+	cluster := vault.NewTestCluster(t, conf, opts)
 	cluster.Start()
 	defer cluster.Cleanup()