RFR: 8335181: Incorrect handling of HTTP/2 GOAWAY frames in HttpClient [v2]

[Jaikiran Pai]

> This is a fresh version of the PR that I had opened here https://github.com/openjdk/jdk/pull/20442. A `git merge` command ended up causing unexpected issues with that old PR.
> 
> The commits in this PR are the ones which were already reviewed and a new one which was done to implement Daniel's suggestion in the review. test repeat 50 of java/net/httpclient had passed without any issues for that old PR. But before integrating this PR, I will rerun all relevant tests again to be sure nothing unexpected shows up.
> 
> Sorry that this has to be reviewed afresh.

Jaikiran Pai has updated the pull request incrementally with four additional commits since the last revision:

 - decrementStreamsCount() in closeAsUnprocessed()
 - add code comment to explain why closeAsUnprocessed() isn't needed
 - Revert "Daniel's suggestion - call closeAsUnprocessed() from handleReset"
   
   This reverts commit 4e56a7c668f5800375b4dea4ab2e2940ca1f888e.
 - Revert "also decrement streams to allow the HttpClient to close"
   
   This reverts commit 5040bf732bd9cb5e2dd7feb532a467991a64cb60.

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/20567/files
  - new: https://git.openjdk.org/jdk/pull/20567/files/5040bf73..fc7158c5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20567&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20567&range=00-01

  Stats: 37 lines in 1 file changed: 15 ins; 4 del; 18 mod
  Patch: https://git.openjdk.org/jdk/pull/20567.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20567/head:pull/20567

PR: https://git.openjdk.org/jdk/pull/20567