OpenJDK 17: sun.util.locale.LocaleSyntaxException

This is part of merging upstream changes from OpenJDK 17.0.3-ga. This CL
updates sun.util.locale.LocaleSyntaxException class.

Bug: 241096650
Test: m
Change-Id: I8ca0ff8d30c96459e8e8a487ed9cc4a3726c185a
diff --git a/ojluni/src/main/java/sun/util/locale/LocaleSyntaxException.java b/ojluni/src/main/java/sun/util/locale/LocaleSyntaxException.java
index 07c0ed3..9cb7b52 100644
--- a/ojluni/src/main/java/sun/util/locale/LocaleSyntaxException.java
+++ b/ojluni/src/main/java/sun/util/locale/LocaleSyntaxException.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -33,6 +33,7 @@
 
 public class LocaleSyntaxException extends Exception {
 
+    @java.io.Serial
     private static final long serialVersionUID = 1L;
 
     private int index = -1;