### Steps to reproduce this issue

```
dubbo.registry.simplified=true 
<dubbo:service interface="org.apache.dubbo.demo.DemoService" register="false" ref="demoService" delay="5000"/>
```

when set dubbo.registry.simplified true. the dubbo.service.register won't take effect because of the `register`  key was simplified and will use default value `true`;

```
URL providerUrl = getProviderUrl(originInvoker);
...
final URL registeredProviderUrl = getRegisteredProviderUrl(providerUrl, registryUrl);
boolean register = registeredProviderUrl.getParameter("register", true);
```
may use `providerUrl` here



private final Invoker<T> originInvoker;
        private Exporter<T> exporter;
        private URL subscribeUrl;
        private URL registerUrl;
        public ExporterChangeableWrapper(Exporter<T> exporter, Invoker<T> originInvoker) {
            this.exporter = exporter;
            this.originInvoker = originInvoker;
        }
        public Invoker<T> getOriginInvoker() {
            return originInvoker;
        }
        @Override
        public Invoker<T> getInvoker() {
            return exporter.getInvoker();
        }
        public void setExporter(Exporter<T> exporter) {
            this.exporter = exporter;
        }
        @Override
        public void unexport() {
            String key = getCacheKey(this.originInvoker);
            bounds.remove(key);
            Registry registry = RegistryProtocol.INSTANCE.getRegistry(originInvoker);
            try {
                registry.unregister(registerUrl);
            } catch (Throwable t) {
                logger.warn(t.getMessage(), t);
            }
            try {
                NotifyListener listener = RegistryProtocol.INSTANCE.overrideListeners.remove(subscribeUrl);