RFR 8171316: Add IMPLEMENTOR property to the release file

[Sundararajan Athijegannathan]

Please review. Bug: https://bugs.openjdk.java.net/browse/JDK-8171316

top level webrev: http://cr.openjdk.java.net/~sundar/8171316/top/webrev.00/
jdk webrev: http://cr.openjdk.java.net/~sundar/8171316/jdk/webrev.00/

Thanks,
-Sundar