More RetryingTest for UDP and NIO tests

**Auto-cherry-pick to `7.0.x` & `6.5.x`**

Author: artembilan

spring-integration-ip/src/test/java/org/springframework/integration/ip/tcp/connection/TcpNioConnectionTests.java

@@ -586,7 +586,7 @@ private static void cleanupCompositeExecutor(CompositeExecutor compositeExec) th
 		TestUtils.<DisposableBean>getPropertyValue(compositeExec, "secondaryTaskExecutor").destroy();
 	}
 
-	@Test
+	@RetryingTest(10)
 	public void testAllMessagesDelivered() throws Exception {
 		final int numberOfSockets = 10;
 		TcpNioServerConnectionFactory factory = new TcpNioServerConnectionFactory(0);

spring-integration-ip/src/test/java/org/springframework/integration/ip/udp/DatagramPacketMulticastSendingHandlerTests.java

@@ -53,7 +53,7 @@
 @DisabledOnOs(value = OS.MAC, disabledReason = "Multicast tests don't work on MacOS")
 public class DatagramPacketMulticastSendingHandlerTests implements TestApplicationContextAware {
 
-	@RetryingTest(10)
+	@RetryingTest(20)
 	public void verifySendMulticast(MulticastCondition multicastCondition) throws Exception {
 		MulticastSocket socket;
 		try {
@@ -122,7 +122,7 @@ public void verifySendMulticast(MulticastCondition multicastCondition) throws Ex
 		socket.close();
 	}
 
-	@RetryingTest(10)
+	@RetryingTest(20)
 	public void verifySendMulticastWithAcks(MulticastCondition multicastCondition) throws Exception {
 		MulticastSocket socket = new MulticastSocket();
 		final int testPort = socket.getLocalPort();

spring-integration-ip/src/test/java/org/springframework/integration/ip/udp/UdpChannelAdapterTests.java

@@ -258,7 +258,7 @@ public void testUnicastSender() {
 	}
 
 	@SuppressWarnings("unchecked")
-	@RetryingTest(10)
+	@RetryingTest(20)
 	public void testMulticastReceiver(MulticastCondition multicastCondition) throws Exception {
 		QueueChannel channel = new QueueChannel(2);
 		MulticastReceivingChannelAdapter adapter =