[jdk21u-dev] RFR: 8342075: HttpClient: improve HTTP/2 flow control checks [v4]

[Alexey Bakhtin]

> Please review the backport of JDK-8342075
> 
> Almost clean backport except for the import section of src/java.net.http/share/classes/jdk/internal/net/http/Http2Connection.java
> 
> Requires JDK-8317808 [1] as a prerequisite to fixing the hanging of the new tests.
> 
> Also, new tests require Http2TestExchange::getConnectionKey() method added by JDK-8335181 [2].
> 
> test/jdk/java/net/httpclient/lib/jdk/httpclient/test/lib/http2/Http2TestExchange.java, test/jdk/java/net/httpclient/lib/jdk/httpclient/test/lib/http2/Http2TestExchangeImpl.java and test/jdk/java/net/httpclient/lib/jdk/httpclient/test/lib/http2/Http2TestServerConnection.java test classes are updated to add  getConnectionKey() implementation
> 
> All jtreg tests for java.net.httpclient are passed
> 
> [1] - https://github.com/openjdk/jdk21u-dev/pull/1426
> [2] - https://github.com/openjdk/jdk/commit/720b44648bcff997278af92746f942b2425298a5#diff-c18c2a070038409f25c08e13c174a95f33840e2deddcc29f6d8306de572a618b

Alexey Bakhtin has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 11 commits:

 - Merge branch 'master' into JDK-8342075-v1
 - Merge master
 - Add Http2TestExchange::getConnectionKey() from JDK-8335181
 - Backport b0ac633b2d0076d64b463b2a6ce19abf6b12c50f
 - Revert "Backport fc98998627443d6e73ac70661f47f48b30525712"
   
   This reverts commit 899abf76e7a381abdfbc30f08a6a5678c0a8065d.
 - Revert "Backport 720b44648bcff997278af92746f942b2425298a5"
   
   This reverts commit a5b7bb4d432c868d598c35f54306e40747071ad7.
 - Revert "Remove extra import"
   
   This reverts commit 480336754274ea62ab2e9b076dcec91f7d483c25.
 - Backport 6273ab97dc1a0d3c1f51ba94694d9594dd7593d4
 - Remove extra import
 - Backport 720b44648bcff997278af92746f942b2425298a5
 - ... and 1 more: https://git.openjdk.org/jdk21u-dev/compare/c874b46e...8b0b0fd6

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

Changes: https://git.openjdk.org/jdk21u-dev/pull/1428/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1428&range=03
  Stats: 1024 lines in 13 files changed: 987 ins; 2 del; 35 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1428.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1428/head:pull/1428

PR: https://git.openjdk.org/jdk21u-dev/pull/1428