[jdk21u-dev] RFR: 8324983: Race in CompileBroker::possibly_add_compiler_threads

[Martin Doerr]

Clean backport of [JDK-8324983](https://bugs.openjdk.org/browse/JDK-8324983).

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Commit messages:
 - Backport 1993652653eab8dd7ce2221a97cd2e401f2dcf56

Changes: https://git.openjdk.org/jdk21u-dev/pull/693/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=693&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8324983
  Stats: 12 lines in 2 files changed: 10 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/693.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/693/head:pull/693

PR: https://git.openjdk.org/jdk21u-dev/pull/693