RFR: 8331495: Limit BasicDirectoryModel/LoaderThreadCount.java to Windows only

[Phil Race]

On Wed, 1 May 2024 16:29:10 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

> As soon as I integrated `test/jdk/javax/swing/plaf/basic/BasicDirectoryModel/LoaderThreadCount.java` #18957, the test started failing in CI on Linux and macOS. There are six failures found so far.
> 
> Before starting code review and later, I ran the test many times on CI and I never saw so many failures.
> 
> To reduce the noise, I'm limiting the test to **Windows only** where it's stable.
> 
> I submitted [JDK-8331494](https://bugs.openjdk.org/browse/JDK-8331494) to make the test more stable on Linux and macOS if possible.

One reviewer is OK here.

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Marked as reviewed by prr (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/19038#pullrequestreview-2033940495