Shenandoah Events

[Ken Dobson]

Sorry I only looked at them from a JMC perspective to verify they worked
there. Should have realized it would affect the Shenandoah tests as well.

Thank you for your comments and assistance, you've been very helpful!

Do you know of a good way to test the performance overhead of these events
when they are enabled?

As well, the goal with these events is to create something similar to the
G1 Heap Layout in JMC (screenshot:
https://gyazo.com/224574751d48804814163c280764bde5). It is used by
selecting a GC event in the table on the right which will play the recorded
heap information beginning at that GC, displaying the Heap Region state
changes in a very similar manner to the Shenandoah Visualizer. Do you have
any recommendations for changes or additional features you think would make
it more useful for Shenandoah?

Thanks,

Ken