RFR (S) 8242089: Shenandoah: per-worker stats should be summed up, not averaged

[Roman Kennke]

Hi Aleksey,

> RFE:
>   https://cr.openjdk.java.net/~shade/8242089/webrev.01/
> 
> Rationale is in the RFE.

Yes. And the RFE is here:
https://bugs.openjdk.java.net/browse/JDK-8242089

> Webrev:
>   https://cr.openjdk.java.net/~shade/8242089/webrev.01/
> 

> Logs before/after:
>   https://cr.openjdk.java.net/~shade/8242089/before.txt
>   https://cr.openjdk.java.net/~shade/8242089/after.txt
> 
> Testing: hotspot_gc_shenandoah, eyeballing logs
> 

Looks good. Thank you!

Roman