RFR: 8373100: Genshen: Control thread can miss allocation failure notification [v3]

[William Kemper]

> In some cases, the control thread may fail to observe an allocation failure. This results in the thread which failed to allocate waiting forever for the control thread to run a cycle. Depending on which thread fails to allocate, the process may not make progress.

William Kemper 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:

 - Merge remote-tracking branch 'jdk/master' into fix-missed-cancellation
 - Improve comment
 - Set requested gc cause under a lock when allocation fails
 - Expand scope of control lock so that it can't miss cancellation notifications

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/28665/files
  - new: https://git.openjdk.org/jdk/pull/28665/files/1081f21e..4c82d21c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28665&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28665&range=01-02

  Stats: 35761 lines in 486 files changed: 23753 ins; 9524 del; 2484 mod
  Patch: https://git.openjdk.org/jdk/pull/28665.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28665/head:pull/28665

PR: https://git.openjdk.org/jdk/pull/28665