RFR(S) More collection set and matrix cleanup

[Aleksey Shipilev]

On 06/27/2017 04:00 PM, Zhengyu Gu wrote:
> Webrev: http://cr.openjdk.java.net/~zgu/shenandoah/cset_matrix_refactor/webrev.00/

*) Can use zero_to_bytes?

   44   Copy::fill_to_bytes(_cset_map, _map_size, 0);
...
   68   Copy::fill_to_bytes(_cset_map, _map_size, 0);

Otherwise good.

-Aleksey