RFR: VerifyJCStressTest should test all heuristics

[Aleksey Shipilev]

http://cr.openjdk.java.net/~shade/shenandoah/verify-jcstress-all/webrev.01/

We have missed unsafe oopDesc operation with traversal heuristics, because no test validates it.
Extended VerifyJCStressTest with all heuristics. (Passive excludes -XX:+ShVerifyOptoBarriers,
because barrier config is odd there).

Testing: hotspot_gc_shenandoah

Thanks,
-Aleksey