RFR: 8228991: Obsolete -XX:UseAdaptiveGCBoundary

[Kim Barrett]

> On Apr 15, 2020, at 10:16 AM, Kim Barrett <kim.barrett at oracle.com> wrote:
> 
>> - maybe add a release note for this to get some more publicity of that change (if we want it)
> 

Here’s the release note, for review.
https://bugs.openjdk.java.net/browse/JDK-8242903