8238270: java.net HTTP/2 client does not decrease stream count when receives 204 response

[Chris Hegarty]

> On 16 Apr 2020, at 19:10, Daniel Fuchs <daniel.fuchs at oracle.com> wrote:
> 
> ... so I have logged https://bugs.openjdk.java.net/browse/JDK-8242999
> to follow up on this.
> ...
> 
> New webrev: http://cr.openjdk.java.net/~dfuchs/webrev_8238270/webrev.01/
> 

This fixes the issue at-hand and is a a good incremental improvement.
Reviewed.

Clearly there is further work that can be done here to; test, verify,
and possibly fix the various permutations that can arise. This work can
be done through the follow-up issue you have logged.

-Chris.