[jdk8u-dev] RFR: 8209023: fix 2 compiler tests to avoid JDK-8208690

[Zdenek Zambersky]

Arm test runs of `Test6891750` on adoptium infra [fail](https://github.com/adoptium/aqa-tests/pull/5646#issuecomment-2383302408) with:

JavaTest Message: Problem cleaning up the following threads:
Thread-10
  at Test6891750.test(Test6891750.java:69)
  at Test6891750.run(Test6891750.java:88)
 ```
 
This simple backport ([JDK-8209023](https://bugs.openjdk.org/browse/JDK-8209023)) should fix that. Backport is not entirely clean because test was [moved / put into java package](https://github.com/openjdk-bots/jdk11u-dev/commit/a0381422ddb56f6cf8fc2fd1a7f111e11925a7d1#diff-b549ddee629b86e132f95ac3eac281c38135208eae656326860a4ab904784e9b) in newer jdk (affecting `@run` line).
 
**Testing:**
GHA: OK (test passes, failures unrelated)

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

Commit messages:
 - Backport b3cf0cf9fcaa25f11f8b5fb8658ecb383d19fc17

Changes: https://git.openjdk.org/jdk8u-dev/pull/590/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=590&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8209023
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/590.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/590/head:pull/590

PR: https://git.openjdk.org/jdk8u-dev/pull/590