RFR: 8301341: LinkedTransferQueue does not respect timeout for poll() [v7]

[Doug Lea]

> This now uses Thread.isVirtual to distinguish spin vs immediate block cases, enabling re-introduction of spin control from the previous version, removing anomalies like this one.

Doug Lea 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 ten additional commits since the last revision:

 - Merge branch 'openjdk:master' into JDK-8301341
 - Accommodate white-box tests; use consistent constructions; minor improvements
 - Merge branch 'openjdk:master' into JDK-8301341
 - Simplify contention handling; fix test
 - Fix inverted test assert; improve internal documentation; simplify code
 - Merge branch 'openjdk:master' into JDK-8301341
 - Overhaul LTQ and SQ to use common blocking and matching mechanics
 - Merge branch 'openjdk:master' into JDK-8301341
 - Use Thread.isVirtual to distinguish spin vs immediate block cases

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/14317/files
  - new: https://git.openjdk.org/jdk/pull/14317/files/060e6774..94148271

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14317&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14317&range=05-06

  Stats: 9836 lines in 305 files changed: 7514 ins; 1081 del; 1241 mod
  Patch: https://git.openjdk.org/jdk/pull/14317.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14317/head:pull/14317

PR: https://git.openjdk.org/jdk/pull/14317