RFR: 8357708: com.sun.jndi.ldap.Connection ignores queued LDAP replies if Connection is subsequently closed [v2]

[Jaikiran Pai]

> Can I please get a review of this change which proposes to address the issue noted in https://bugs.openjdk.org/browse/JDK-8357708?
> 
> As noted in the issue, the current code in `com.sun.jndi.ldap.Connection.readReply()` is susceptible to throwing a `ServiceUnavailableException` even when the LDAP replies have already been received and queued for processing. The JBS issue has additional details about how that can happen.
> 
> The commit in this PR simplifies the code in `com.sun.jndi.ldap.LdapRequest` to make sure it always gives out the replies that have been queued when the `LdapRequest.getReplyBer()` gets invoked. One of those queued values could be markers for a cancelled or closed request. In that case, the `getReplyBer()`, like previously, continues to throw the right exception. With this change, the call to `replies.take()` or `replies.poll()` (with an infinite timeout) is no longer expected to hang forever, if the `Connection` is closed (or the request cancelled). This then allows us to remove the connection closure (`sock == null`) check in `Connection.readReply()`.
> 
> A new jtreg test has been introduced to reproduce this issue and verify the fix. The test reproduces this issue consistently when the source fix isn't present. With the fix present, even after several thousand runs of this test, the issue no longer reproduces.
> 
> tier1, tier2 and tier3 tests continue to pass with this change. I've marked the fix version of this issue for 26 and I don't plan to push this for 25.

Jaikiran Pai 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 three additional commits since the last revision:

 - merge latest from master branch
 - add test
 - 8357708: com.sun.jndi.ldap.Connection ignores queued LDAP replies if Connection is subsequently closed

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/25449/files
  - new: https://git.openjdk.org/jdk/pull/25449/files/908e4b60..5a6012e6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25449&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25449&range=00-01

  Stats: 120533 lines in 2273 files changed: 72238 ins; 31047 del; 17248 mod
  Patch: https://git.openjdk.org/jdk/pull/25449.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25449/head:pull/25449

PR: https://git.openjdk.org/jdk/pull/25449