[jdk17u-dev] RFR: 8276125: RunThese24H.java SIGSEGV in JfrThreadGroup::thread_group_id

[Liang Mao]

Clean backport for fixing JFR crash. The root cause is creating threads in JNI function can overlap with the JFR safepoint op and accessing a NULL threadobj. The original commit fixed the potential NULL access.

Additional testing:
 - [x] Linux aarch64 server fastdebug,  test/jdk/jdk/jfr passed

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Commit messages:
 - Backport a885aab696777c99c8c4c5d9a46afc5fe0a4fe47

Changes: https://git.openjdk.org/jdk17u-dev/pull/2179/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=2179&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8276125
  Stats: 6 lines in 1 file changed: 4 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/2179.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/2179/head:pull/2179

PR: https://git.openjdk.org/jdk17u-dev/pull/2179