8256427: Test com/sun/jndi/dns/ConfigTests/PortUnreachable.java does not work on AIX

Reviewed-by: jiefu, mbaesken

Author: RealCLanger

test/jdk/com/sun/jndi/dns/ConfigTests/PortUnreachable.java

@@ -32,6 +32,8 @@
  *          Unreachable packet is received, we fail quickly and don't wait for
  *          the full timeout interval. This could be caused, for example, by a
  *          dead DNS server or a flakey router.
+ *          On AIX, no ICMP Destination Unreachable is received, so skip test.
+ * @requires os.family != "aix"
  * @library ../lib/
  * @modules java.base/sun.security.util
  * @run main/othervm -Djdk.net.usePlainDatagramSocketImpl=false PortUnreachable