RFR: 8329705: Add missing Application thread checks to platform specific a11y methods

[Kevin Rushforth]

On Thu, 4 Apr 2024 21:55:11 GMT, Alexander Zuev <kizune at openjdk.org> wrote:

> Added missing checks;
> Added a manual regression test;

Reviewers: @kevinrushforth @arapte

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PR Comment: https://git.openjdk.org/jfx/pull/1436#issuecomment-2038349547