fix : The client and server are connected synchronously

hippo4j-rpc/src/test/java/cn/hippo4j/rpc/support/NettyServerSupportTest.java

@@ -27,7 +27,7 @@ import java.io.IOException;
 public class NettyServerSupportTest {
 
     @Test
-    public void bind() throws IOException {
+    public synchronized void bind() throws IOException {
         NettyServerSupport support = new NettyServerSupport(() -> 8891, InstanceServerLoader.class);
         support.bind();
         while (!support.isActive()) {