[JDK 11] RFR 8187069: The case auto failed with the "java.lang.ClassNotFoundException: IPv6NameserverPlatformParsingTest" exception

[Chris Yin]

Please review below one line change for manual test case 
com/sun/jndi/dns/Test6991580.java to build test class automatically which will 
be used in manual steps, thanks

bug: https://bugs.openjdk.java.net/browse/JDK-8187069 
<https://bugs.openjdk.java.net/browse/JDK-8187069>

Review change as below:

diff -r 2d3e99a72541 test/jdk/com/sun/jndi/dns/Test6991580.java
--- a/test/jdk/com/sun/jndi/dns/Test6991580.java        Wed Jun 27 17:02:41 
2018 -0700
+++ b/test/jdk/com/sun/jndi/dns/Test6991580.java        Thu Jun 28 09:50:37 
2018 +0800
@@ -37,6 +37,7 @@
  * @summary IPv6 Nameservers in resolv.conf throws NumberFormatException
  * @modules java.desktop
  *          jdk.naming.dns/com.sun.jndi.dns
+ * @build IPv6NameserverPlatformParsingTest
  * @run main/manual Test6991580
  */

Regards,
Chris