RFR: Purge batched matrix cleanup

[Aleksey Shipilev]

On 10/13/2017 05:36 PM, Aleksey Shipilev wrote:
> http://cr.openjdk.java.net/~shade/shenandoah/matrix-no-batched/webrev.01/
> 
> My suggestion is to ditch the batched matrix cleanup code, and leverage async recycling for doing
> the right thing. Allocators would normally assist with matrix cleanup, if async recycling is late.
> The experiments show this adds around 100us latency on allocation path with 32K regions (which is
> above our target anyhow), and it is negligible with the 4K target.

Oh, and by that I mean it adds 0..6ms to the Concurrent Cleanup phase with 4K regions.

-Aleksey