RFR: 8322846: Running with -Djdk.tracePinnedThreads set can hang [v2]

[Alan Bateman]

> -Djdk.tracePinnedThreads is a debugging option that dates from early development in the loom repo to identify pinned threads. It has several issues and this tracing option will eventually be removed (use the JFR events instead). Several hangs have been reported when running with the system property set. The "hangs" stem from the onPinned callback executing while the virtual thread is in a transition state (typically parking). If the virtual parks while printing the stack trace then it works like a nested park where the thread state is never restored. Contention on the System.out can also lead to deadlock when there are platform and pinned virtual threads printing to System.out around the same time.
> 
> This PR brings over the changes from the loom repo to avoid these hangs. The changes mean the stack trace is only printed to System.out when the PrintStream lock can be acquired without blocking. It also restores the thread state after printing. An alternative to not printing traces would of course be to queue the traces so they are printed by another thread but this is just adding complexity for a debugging option that we want to go away.

Alan Bateman 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:

 - Expand TracePinnedThreads.testContention test description
 - Merge
 - Initial commit

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17221/files
  - new: https://git.openjdk.org/jdk/pull/17221/files/15993866..ab8a2bcb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17221&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17221&range=00-01

  Stats: 2985 lines in 239 files changed: 1868 ins; 364 del; 753 mod
  Patch: https://git.openjdk.org/jdk/pull/17221.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17221/head:pull/17221

PR: https://git.openjdk.org/jdk/pull/17221