Add test for auth violations during reconnect

Introduce a new test case to reproduce issue #1320, focusing on handling authorization violations during reconnections. It also makes the `closeSocketLock` in `NatsConnection` package-private to facilitate testing.

Author: ajax-surovskyi-y

src/test/java/io/nats/client/impl/AuthViolationDuringReconnect.java

@@ -76,7 +76,7 @@ private static void restartServer(AtomicReference<NatsTestServer> ts, int port)
 
     private static void subscribe(Dispatcher d) {
         latch = new CountDownLatch(1);
-        for (int i = 0; i < 500_000; i++) {
+        for (int i = 0; i < 10_000; i++) {
             String subject = "test_" + i;
             subscriptions.add(subject);
             d.subscribe(subject);