[jdk25u-dev] RFR: 8360702: runtime/Thread/AsyncExceptionTest.java timed out

[Roland Mesde]

Backporting JDK-8360702: runtime/Thread/AsyncExceptionTest.java timed out.

This PR fixes the test timeouts by removing synchronization that allowed async exceptions to interrupt ForkJoinPool code when using virtual threads.

For parity with Oracle JDK.

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

make test TEST=test/hotspot/jtreg/runtime/Thread/AsyncExceptionOnMonitorEnter.java
make test TESTtest/hotspot/jtreg/runtime/Thread/AsyncExceptionTest.java

Results attached:

[windows-x64-specific-test.log](https://github.com/user-attachments/files/25394460/windows-x64-specific-test.log)
[windows-x64-specific-2-test.log](https://github.com/user-attachments/files/25394461/windows-x64-specific-2-test.log)
[macos-aarch64-specific-test.log](https://github.com/user-attachments/files/25394462/macos-aarch64-specific-test.log)
[macos-aarch64-specific-2-test.log](https://github.com/user-attachments/files/25394466/macos-aarch64-specific-2-test.log)
[linux-x64-specific-test.log](https://github.com/user-attachments/files/25394468/linux-x64-specific-test.log)
[linux-x64-specific-2-test.log](https://github.com/user-attachments/files/25394469/linux-x64-specific-2-test.log)
[linux-aarch64-specific-test.log](https://github.com/user-attachments/files/25394470/linux-aarch64-specific-test.log)
[linux-aarch64-specific-2-test.log](https://github.com/user-attachments/files/25394471/linux-aarch64-specific-2-test.log)

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

Commit messages:
 - Backport 6f03c7808de2b07b1e501d05b1bb7d5bfde5e393

Changes: https://git.openjdk.org/jdk25u-dev/pull/274/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk25u-dev&pr=274&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8360702
  Stats: 51 lines in 2 files changed: 20 ins; 18 del; 13 mod
  Patch: https://git.openjdk.org/jdk25u-dev/pull/274.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u-dev.git pull/274/head:pull/274

PR: https://git.openjdk.org/jdk25u-dev/pull/274