8023326: [TESTBUG] java/net/CookieHandler/LocalHostCookie.java misplaced try/finally

Summary: amended test to be more robust to set of potential exceptions thrown
Reviewed-by: chegar, khazra

test/java/net/CookieHandler/LocalHostCookie.java

@@ -72,9 +72,11 @@ public class LocalHostCookie {
                 }
             }
         } finally {
+            if (s != null) {
                 s.stopServer();
             }
         }
+    }
 
     class Server {
         HttpServer server;
@@ -96,9 +98,11 @@ public class LocalHostCookie {
         }
 
         public void stopServer() {
+            if (server != null) {
                 server.stop(0);
             }
         }
+    }
 
     class MyCookieHandler implements HttpHandler {