### Environment

* Dubbo version: 3.0

### Steps to reproduce this issue
翻看github构建日志本来是去找GenericServiceTest为啥常常出现java.lang.IllegalStateException: Failed to check the status of the service org.apache.dubbo.config.spring.api.LocalMissClass的线索，相关的线索没找到，却找到了这个
2021-09-04T20:19:48.3933128Z [04/09/21 20:19:47:427 UTC] main  WARN integration.RegistryProtocol:  [DUBBO] unsubscribe listener == null, dubbo version: 3.0.3-SNAPSHOT, current host: 172.17.16.1
2021-09-04T20:19:48.3934495Z java.lang.IllegalArgumentException: unsubscribe listener == null
2021-09-04T20:19:48.3936385Z 	at org.apache.dubbo.registry.support.AbstractRegistry.unsubscribe(AbstractRegistry.java:329)
2021-09-04T20:19:48.3938947Z 	at org.apache.dubbo.registry.support.FailbackRegistry.unsubscribe(FailbackRegistry.java:328)
2021-09-04T20:19:48.3942540Z 	at org.apache.dubbo.registry.ListenerRegistryWrapper.unsubscribe(ListenerRegistryWrapper.java:134)
2021-09-04T20:19:48.3945186Z 	at org.apache.dubbo.registry.integration.RegistryProtocol$ExporterChangeableWrapper.unexport(RegistryProtocol.java:876)
2021-09-04T20:19:48.3948433Z 	at org.apache.dubbo.registry.integration.RegistryProtocol$DestroyableExporter.unexport(RegistryProtocol.java:669)
2021-09-04T20:19:48.3950662Z 	at org.apache.dubbo.config.ServiceConfig.unexport(ServiceConfig.java:187)
2021-09-04T20:19:48.3952706Z 	at org.apache.dubbo.config.bootstrap.DubboBootstrap.lambda$unexportServices$9(DubboBootstrap.java:1487)
2021-09-04T20:19:48.3954404Z 	at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
2021-09-04T20:19:48.3956255Z 	at org.apache.dubbo.config.bootstrap.DubboBootstrap.unexportServices(DubboBootstrap.java:1484)
2021-09-04T20:19:48.3958714Z 	at org.apache.dubbo.config.bootstrap.DubboBootstrap.destroy(DubboBootstrap.java:1635)
2021-09-04T20:19:48.3960885Z 	at org.apache.dubbo.config.bootstrap.DubboBootstrap.reset(DubboBootstrap.java:239)
2021-09-04T20:19:48.3963018Z 	at org.apache.dubbo.config.bootstrap.DubboBootstrap.reset(DubboBootstrap.java:225)
2021-09-04T20:19:48.3965492Z 	at org.apache.dubbo.config.spring.schema.GenericServiceTest.tearDown(GenericServiceTest.java:67)
并且不止这一个测试类抛这个异常，有十多个测试类都抛这个东西，看了看代码，感觉应该是重复注销导致的，RegistryProtocol注销listener前检查一下是否为null应该就能避免这个异常了。
}
    @Test
    public void testLargeReferences() throws InterruptedException {
        int amount = 10000;
        ModuleConfigManager configManager = DubboBootstrap.getInstance().getApplicationModel().getDefaultModule().getConfigManager();
        ApplicationConfig applicationConfig = new ApplicationConfig();
        applicationConfig.setName("test-app");
        MetadataReportConfig metadataReportConfig = new MetadataReportConfig();
        metadataReportConfig.setAddress("metadata://");
        ConfigCenterConfig configCenterConfig = new ConfigCenterConfig();
        configCenterConfig.setAddress("diamond://");
        testInitReferences(0, amount, applicationConfig, metadataReportConfig, configCenterConfig);
        configManager.clear();
        testInitReferences(0, 1, applicationConfig, metadataReportConfig, configCenterConfig);
        configManager.clear();
        long t1 = System.currentTimeMillis();
        int nThreads = 8;
        ExecutorService executorService = Executors.newFixedThreadPool(nThreads);
        for (int i = 0; i < nThreads; i++) {
            int perCount = (int) (1.0 * amount / nThreads);
            int start = perCount * i;
            int end = start + perCount;
            if (i == nThreads - 1) {
                end = amount;
            }
            int finalEnd = end;
            System.out.println(String.format("start thread %s: range: %s - %s, count: %s", i, start, end, (end - start)));
            executorService.submit(() -> {
                testInitReferences(start, finalEnd, applicationConfig, metadataReportConfig, configCenterConfig);
            });