[jdk25u-dev] RFR: 8373485: JFR Crash during sampling: assert(jt->has_last_Java_frame()) failed: invariant

[Roland Mesde]

Backporting JDK-8373485: JFR Crash during sampling:  assert(jt->has_last_Java_frame()) failed: invariant.

The fix adds the missing memory barrier to ensure proper load ordering when sampling native threads.

For parity with Oracle JDK.

Ran related tests on linux-x64, linux-aarch64, macos-aarch64 and windows-x64:

make test TEST="jdk_jfr"

Results attached:

[linux-aarch64-specific-test.log](https://github.com/user-attachments/files/24649832/linux-aarch64-specific-test.log)
[linux-x64-specific-test.log](https://github.com/user-attachments/files/24649833/linux-x64-specific-test.log)
[macos-aarch64-specific-test.log](https://github.com/user-attachments/files/24649834/macos-aarch64-specific-test.log)
[windows-x64-specific-test.log](https://github.com/user-attachments/files/24649835/windows-x64-specific-test.log)

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Commit messages:
 - Merge branch 'openjdk:master' into JDK-8373485-V25
 - Backport 543a972222118155e4c72c6f2d32d154c5dfd442

Changes: https://git.openjdk.org/jdk25u-dev/pull/145/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk25u-dev&pr=145&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8373485
  Stats: 11 lines in 1 file changed: 7 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk25u-dev/pull/145.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u-dev.git pull/145/head:pull/145

PR: https://git.openjdk.org/jdk25u-dev/pull/145