RFR(S): ShenandoahCollectionSet refactor

[Aleksey Shipilev]

On 06/02/2017 06:29 PM, Zhengyu Gu wrote:
> http://cr.openjdk.java.net/~zgu/shenandoah/one_cset/webrev.00/

Awesome. One step closer to ditching all RegionSets, and just redoing them as
the accessors over SH bitmaps.

Comments:

 *) ShenandoahCollectionSet::print -- I don't think there is a need in
debug_only() there, it is not supposed to be highly performant anyway.

 *) Can you turn _cset_map into char*? sizeof(char) == 1 is guaranteed by
Standard, sizeof(bool), on the other hand...

 *) Typo "Should not be":

  assert(!in_collection_set(region), "Humongous region should not in collection
set");

 *) So we have removed r->set_in_collection_set(false) in cleanups, because now
collection_set()->clear() handles the same, right?

Thanks,
-Aleksey