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

### Environment

* Dubbo version: 2.7.0
* Operating System version: mac
* Java version: 1.8

### Steps to reproduce this issue

1.  `AbstractClient#initConnectStatusCheckCommand` set break point at `  !isConnected()`.
2. `AbstractClient#close()` set break point here.    
3.  start client first, start provider and then shutdown provider gracefully , let method `AbstractClient.close()` be executed. Then select step `1` and trigger the thread to execute `!isConnected`, here will always try to connect the offline machine.

Pls. provide [GitHub address] to reproduce this issue.

### Expected Result

What do you expected from the above steps？

When the server goes offline, the client will not reconnect the offline machine.

### Actual Result

What actually happens?

The client reconnects the offline machine every 2 seconds and causes a large number of arp packets(because ip is recycled and not available now).
public void setRegistry(Registry registry) {
        this.registry = registry;
    }
    public void subscribe(URL url) {
        setConsumerUrl(url);
        consumerConfigurationListener.addNotifyListener(this);
        serviceConfigurationListener = new ReferenceConfigurationListener(this, url);
        registry.subscribe(url, this);
    }
    @Override
    public void destroy() {
        if (isDestroyed()) {
            return;
        }
        
        try {
            if (getConsumerUrl() != null && registry != null && registry.isAvailable()) {
                registry.unsubscribe(getConsumerUrl(), this);
            }
            DynamicConfiguration.getDynamicConfiguration()
                    .removeListener(ApplicationModel.getApplication(), consumerConfigurationListener);
        } catch (Throwable t) {
            logger.warn("unexpected error when unsubscribe service " + serviceKey + "from registry" + registry.getUrl(), t);
        }
        super.destroy(); 
        try {
            destroyAllInvokers();
        } catch (Throwable t) {
            logger.warn("Failed to destroy service " + serviceKey, t);
        }