- [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).
}
    private URL overrideWithConfigurators(List<Configurator> configurators, URL url) {
        if (CollectionUtils.isNotEmpty(configurators)) {
            for (Configurator configurator : configurators) {
                url = configurator.configure(url);
            }
        }
        return url;
    }
    /**
     * Close all invokers
     */
    private void destroyAllInvokers() {
        Map<String, Invoker<T>> localUrlInvokerMap = this.urlInvokerMap; 
        if (localUrlInvokerMap != null) {
            for (Invoker<T> invoker : new ArrayList<Invoker<T>>(localUrlInvokerMap.values())) {
                try {
                    invoker.destroy();
                } catch (Throwable t) {
                    logger.warn("Failed to destroy service " + serviceKey + " to provider " + invoker.getUrl(), t);
                }
            }
            localUrlInvokerMap.clear();
        }
        invokers = null;
    }
    /**
     * Check whether the invoker in the cache needs to be destroyed
     * If set attribute of url: refer.autodestroy=false, the invokers will only increase without decreasing,there may be a refer leak
     *