Follow up to https://github.com/openjdk/jdk/pull/19482 that was causing issues when the PrintMountedVirtualTest.java was running with `JTREG_TEST_THREAD_FACTORY=Virtual` in the loom repo.
- Fixes issues where the test observes the thread during transitions. - Fixes a potential issue in the test where CountDownLatch.countDown unparks the main (virtual) thread and the main thread observes the dummy thread is transition . ------------- Commit messages: - 8334215: Fix PrintMountVThread if FACTORY=Virtual Changes: https://git.openjdk.org/jdk/pull/19744/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19744&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8334215 Stats: 15 lines in 2 files changed: 4 ins; 3 del; 8 mod Patch: https://git.openjdk.org/jdk/pull/19744.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/19744/head:pull/19744 PR: https://git.openjdk.org/jdk/pull/19744
