8324234: Use reserved IP for java.net testing

Some tests like test/jdk/java/net/Socket/B8312065.java use specific IPs (like 192.168.255.255) taking the assumption that the address is not going to be assigned. This doesn't always hold true, as 192.168.255.255 for example is a valid address.

RFC 5737 [1] defines specific ranges of IP addresses that may are reserved for these exact purpose and that will never be assigned. Let's make sure to use an IP in this range, like 192.0.2.1 for example.

The specific test test/jdk/java/net/Socket/B8312065.java was introduced with https://git.openjdk.org/jdk17u-dev/pull/1639.

[1] https://www.rfc-editor.org/rfc/rfc5737

Author: luhenry

test/jdk/java/net/Socket/B8312065.java

@@ -73,8 +73,8 @@ public static void main(String[] args) throws Exception {
 
         try {
             Socket socket = new Socket();
-            // There is no good way to mock SocketTimeoutException, just assume 192.168.255.255 is not in use
-            socket.connect(new InetSocketAddress("192.168.255.255", 8080), timeoutMillis);
+            // There is no good way to mock SocketTimeoutException, use reserved IP from https://www.rfc-editor.org/rfc/rfc5737
+            socket.connect(new InetSocketAddress("192.0.2.1", 8080), timeoutMillis);
         } catch (SocketTimeoutException e) {
             long duration = TimeUnit.MILLISECONDS.convert(System.nanoTime() - startTime, TimeUnit.NANOSECONDS);
             if (duration >= timeoutMillis) {