RFR: JDK-8241602 jlink does not produce reproducible jimage files

[Jim Laskey]

This fix addresses the inconsistent ordering by jimage content by jlink from run to run. Bottom line, the implementer was using HashSet without defining hashcode/equals for the Set entry classes.

webrev: http://cr.openjdk.java.net/~jlaskey/8241602/webrev-00 <http://cr.openjdk.java.net/~jlaskey/8241602/webrev-00>
jbs: https://bugs.openjdk.java.net/browse/JDK-8241602 <https://bugs.openjdk.java.net/browse/JDK-8241602>

Cheers,

-- Jim