Issue #4550 XmlConfiguration argument matching

Improve argument matching by:
 + can unbox from any Number to any Number

Signed-off-by: Greg Wilkins <gregw@webtide.com>

jetty-util/src/main/java/org/eclipse/jetty/util/TypeUtil.java

@@ -752,6 +752,7 @@ public static boolean isUnboxable(Class<?> type, Object arg)
             return true;
 
         Class<?> c = __unbox.get(type);
-        return arg.getClass() == __unbox.get(type);
+        Class<?> ac = arg.getClass();
+        return ac == __unbox.get(type) || (Number.class.isAssignableFrom(c) && Number.class.isAssignableFrom(ac));
     }
 }