测试环境直连多个地址报错

- [ ] I have searched the [issues](https://github.com/apache/dubbo/issues) of this repository and believe that this is not a duplicate.

## 测试环境直连多个地址报错
### 环境

* Dubbo version: 2.7.15
* Operating System version: windows 10
* Java version: 1.8_282

### 配置

1. spring-consumer.xml
```

```
2. 报错信息
```
java.lang.ClassCastException: org.apache.dubbo.rpc.protocol.FilterNode cannot be cast to org.apache.rpc.cluster.support.migration.MigrationClusterInvoker
at org.apache.dubbo.rpc.cluster.support.registry.ZoneAwareClusterInvoker.list(ZoneAwareClusterInvoker.java:127)
```
我看官方文档描述如果有多个地址则用分号隔开。如果只有一个地址运行不报错，如果有多个地址则报错