RFR: 8308027: GetThreadListStackTraces/OneGetThreadListStackTraces.java should be skipped when thread factory is used

[Leonid Mesnik]

The test fails with virtual thread factory. 
There is no good way to adopt it for virtual thread factory. So let skip it's execution with it permanently.

The property support has been added to the jtregby
https://bugs.openjdk.org/browse/CODETOOLS-7903931

I use
`@requires test.thread.factory == null`
and not
`@requires test.thread.factory != "Virtual"`
because I don't think that it makes sense to run it with any potential test thread factory, like "VirtualStress"

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Commit messages:
 - 8308027: GetThreadListStackTraces/OneGetThreadListStackTraces.java should be skipped when thread factory is used

Changes: https://git.openjdk.org/jdk/pull/27507/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27507&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8308027
  Stats: 3 lines in 2 files changed: 1 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27507.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27507/head:pull/27507

PR: https://git.openjdk.org/jdk/pull/27507