问题描述：发现服务关停过程中未正常调用ServiceDiscovery的unregister方法

问题原因：
1. preDestroy中，先执行destroyRegistries()，再执行destroyServiceDiscoveries()，最后执行unregisterServiceInstance()
~~~
    @Override
    public void preDestroy() {
        synchronized (destroyLock) {
            if (isStopping() || isStopped()) {
                return;
            }
            onStopping();

            destroyRegistries();
            destroyServiceDiscoveries();
            destroyMetadataReports();

            unRegisterShutdownHook();
            if (asyncMetadataFuture != null) {
                asyncMetadataFuture.cancel(true);
            }
            unregisterServiceInstance();
        }
    }
~~~
2. destroyRegistries()方法中调用destroyAll()方法，将容器registries中所有Registry进行销毁并从容器registries中移除，此时容器registries中已经没有数据，并且所有与注册中心的通信工具（如nacos的NamingService，zk的CuratorFramework）都被销毁
~~~
   public void destroyAll() {
        if (!destroyed.compareAndSet(false, true)) {
            return;
        }

        if (LOGGER.isInfoEnabled()) {
            LOGGER.info("Close all registries " + getRegistries());
        }
        // Lock up the registry shutdown process
        lock.lock();
        try {
            for (Registry registry : getRegistries()) {
                try {
                    registry.destroy();
                } catch (Throwable e) {
                    LOGGER.warn(e.getMessage(), e);
                }
            }
            registries.clear();
        } finally {
            // Release the lock
            lock.unlock();
        }
    }
~~~
3. destroyServiceDiscoveries()、unregisterServiceInstance()执行时，已经无法从容器registries中获取ServiceDiscoveries（即使能获取到，与注册中心的通信工具NamingService\CuratorFramework等已经被销毁无法使用）

修改方法：将unregisterServiceInstance()调整到destroyRegistries()之前，并删除destroyServiceDiscoveries()
~~~
   @Override
    public void preDestroy() {
        synchronized (destroyLock) {
            if (isStopping() || isStopped()) {
                return;
            }
            onStopping();
            
            unregisterServiceInstance();
            destroyRegistries();
            destroyMetadataReports();

            unRegisterShutdownHook();
            if (asyncMetadataFuture != null) {
                asyncMetadataFuture.cancel(true);
            }

        }
    }
~~~

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package org.apache.dubbo.config.deploy;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.config.ConfigurationUtils;
import org.apache.dubbo.common.config.Environment;
import org.apache.dubbo.common.config.ReferenceCache;