RFR: Print message when heuristics changes the setting ergonomically

[Roman Kennke]

Good!

On Fri, Mar 2, 2018 at 1:02 PM, Aleksey Shipilev <shade at redhat.com> wrote:
> http://cr.openjdk.java.net/~shade/shenandoah/heuristics-ergo-msg/webrev.01/
>
> This makes all heuristics print their decisions about the flags they set ergonomically, e.g.:
>
> [0.004s][info][gc] Heuristics ergonomically sets -XX:ShenandoahAllocationThreshold=10
> [0.004s][info][gc] Heuristics ergonomically sets -XX:ShenandoahUncommitDelay=5000
> [0.004s][info][gc] Heuristics ergonomically sets -XX:ShenandoahGuaranteedGCInterval=30000
> [0.004s][info][gc] Heuristics ergonomically sets -XX:ShenandoahGarbageThreshold=20
>
> Testing: hotspot_gc_shenandoah
>
> Thanks,
> -Aleksey
>