RFR: JDK-8028430 JDI: ReferenceType.visibleMethods() return wrong visible methods

[Staffan Larsen]

All,

ReferenceType.visibleMethods() has some problems with diamond shaped interface hierarchies. There is more information on the problem in the bug report. 

The solution here is to maintain a list of interfaces that we have visited so that we do not visit interfaces (above the top of the diamond) more than once.

This change is targeted for jdk9 so I will hold on to it until the repos open up.

webrev: http://cr.openjdk.java.net/~sla/8028430/webrev.00/
bug: https://bugs.openjdk.java.net/browse/JDK-8028430

Thanks,
/Staffan