RFR (T) 8234355: Buffer overflow in jcmd GC.class_stats due to too many classes

[coleen . phillimore]

Summary: Remove use of GC.class_stats in testing and failure analysis 
(plan to deprecate)

See bug for more details.
open webrev at http://cr.openjdk.java.net/~coleenp/2019/8234355.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8234355

Ran tier8 overnight.

Thanks,
Coleen