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

[duke]

Changeset: da1abd18
Author:    Daniel Fuchs <dfuchs at openjdk.org>
Date:      2020-04-20 13:15:45 +0000
URL:       https://git.openjdk.java.net/mobile/commit/da1abd18

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

The HTTP/2 Stream is updated to register a trivial data subscriber in case of 204 so that the END_STREAM is correctly processed.

Reviewed-by: chegar

! src/java.net.http/share/classes/jdk/internal/net/http/ExchangeImpl.java
! src/java.net.http/share/classes/jdk/internal/net/http/Stream.java
+ test/jdk/java/net/httpclient/Response204V2Test.java
! test/jdk/java/net/httpclient/http2/server/Http2TestExchangeImpl.java