Fix unstable QuicServerTest.testRebind

Closes #5941

Author: ahus1

vertx-core/src/test/java/io/vertx/tests/net/quic/QuicServerTest.java

@@ -19,6 +19,7 @@
 import io.netty.util.NetUtil;
 import io.vertx.core.*;
 import io.vertx.core.buffer.Buffer;
+import io.vertx.core.internal.ContextInternal;
 import io.vertx.core.internal.quic.QuicConnectionInternal;
 import io.vertx.core.internal.quic.QuicStreamInternal;
 import io.vertx.core.net.*;
@@ -891,12 +892,21 @@ private void testWriteWhenClosed(boolean write) throws Exception {
 
   @Test
   public void testRebind() {
-    Deployable deployable = ctx -> {
-      QuicServer server = QuicServer.create(vertx, SSL_OPTIONS);
-      server.handler(connection -> {
+    Deployable deployable = new Deployable() {
+      private QuicServer server;
+      @Override
+      public Future<?> deploy(Context ctx) {
+        server = QuicServer.create(vertx, SSL_OPTIONS);
+        server.handler(connection -> {
 
-      });
-      return server.bind(SocketAddress.inetSocketAddress(9999, "localhost"));
+        });
+        return server.bind(SocketAddress.inetSocketAddress(9999, "localhost"));
+      }
+
+      @Override
+      public Future<?> undeploy(Context context) {
+        return server.close();
+      }
     };
     int num = 4;
     for (int i = 0;i < num;i++) {