Preserve previous alicloud machine class naming

```improvement user
The previous naming scheme for Alicloud machine classes is now preserved (`<namespace>-<pool-name>-<zone-name>` instead of `<namespace>-<pool-name>-z<zone-index>`).
```

controllers/provider-alicloud/pkg/controller/worker/machines.go

@@ -150,7 +150,7 @@ func (w *workerDelegate) generateMachineConfig(ctx context.Context) error {
 
 			var (
 				machineClassSpecHash = worker.MachineClassHash(machineClassSpec, shootVersionMajorMinor)
-				deploymentName       = fmt.Sprintf("%s-%s-z%d", w.worker.Namespace, pool.Name, zoneIndex+1)
+				deploymentName       = fmt.Sprintf("%s-%s-%s", w.worker.Namespace, pool.Name, zone)
 				className            = fmt.Sprintf("%s-%s", deploymentName, machineClassSpecHash)
 			)
 

controllers/provider-alicloud/pkg/controller/worker/machines_test.go

@@ -314,10 +314,10 @@ var _ = Describe("Machines", func() {
 					machineClassPool2Zone1 = useDefaultMachineClass(defaultMachineClass, "vSwitchID", vswitchZone1, "zoneID", zone1)
 					machineClassPool2Zone2 = useDefaultMachineClass(defaultMachineClass, "vSwitchID", vswitchZone2, "zoneID", zone2)
 
-					machineClassNamePool1Zone1 = fmt.Sprintf("%s-%s-z1", namespace, namePool1)
-					machineClassNamePool1Zone2 = fmt.Sprintf("%s-%s-z2", namespace, namePool1)
-					machineClassNamePool2Zone1 = fmt.Sprintf("%s-%s-z1", namespace, namePool2)
-					machineClassNamePool2Zone2 = fmt.Sprintf("%s-%s-z2", namespace, namePool2)
+					machineClassNamePool1Zone1 = fmt.Sprintf("%s-%s-%s", namespace, namePool1, zone1)
+					machineClassNamePool1Zone2 = fmt.Sprintf("%s-%s-%s", namespace, namePool1, zone2)
+					machineClassNamePool2Zone1 = fmt.Sprintf("%s-%s-%s", namespace, namePool2, zone1)
+					machineClassNamePool2Zone2 = fmt.Sprintf("%s-%s-%s", namespace, namePool2, zone2)
 
 					machineClassHashPool1Zone1 = worker.MachineClassHash(machineClassPool1Zone1, shootVersionMajorMinor)
 					machineClassHashPool1Zone2 = worker.MachineClassHash(machineClassPool1Zone2, shootVersionMajorMinor)