RFR: 8343129: Disable unstable check of ThreadsListHandle.sanity_vm ThreadList values

[SendaoYan]

Hi all,
We have observed `ThreadsListHandle.sanity_vm failed with unequal ThreadList values` several times on linux-x64 and linux-aarch64, by jdk17u/jdk21u/jdk24 etc.
Before the root cause of the test failure has been fixed, should we disable the unstable check of ThreadsListHandle.sanity_vm ThreadList values, to make less of CI noisy.

Additional testing:

- [ ] release build and run the `gtest/GTestWrapper.java` on linux-x64
- [ ] fastdebug build and run the `gtest/GTestWrapper.java` on linux-x64
- [ ] slowdebug build and run the `gtest/GTestWrapper.java` on linux-x64

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

Commit messages:
 - 8343129: Disable unstable check of ThreadsListHandle.sanity_vm ThreadList values

Changes: https://git.openjdk.org/jdk/pull/21734/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21734&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343129
  Stats: 20 lines in 1 file changed: 10 ins; 0 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/21734.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21734/head:pull/21734

PR: https://git.openjdk.org/jdk/pull/21734