[jdk21u-dev] RFR: 8317808: HTTP/2 stream cancelImpl may leave subscriber registered [v2]

[Alexey Bakhtin]

> Clean backport of JDK-8317808
> 
> All jtreg tests for java.net.httpclient are passed

Alexey Bakhtin has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Backport 6273ab97dc1a0d3c1f51ba94694d9594dd7593d4
 - Remove extra import
 - Backport 720b44648bcff997278af92746f942b2425298a5
 - Backport fc98998627443d6e73ac70661f47f48b30525712

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

Changes:
  - all: https://git.openjdk.org/jdk21u-dev/pull/1426/files
  - new: https://git.openjdk.org/jdk21u-dev/pull/1426/files/fa55d4a5..c0f83e97

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1426&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1426&range=00-01

  Stats: 1362 lines in 13 files changed: 587 ins; 516 del; 259 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1426.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1426/head:pull/1426

PR: https://git.openjdk.org/jdk21u-dev/pull/1426