RFR: 8281535: Create a regression test for JDK-4670051

[Manukumar V S]

On Wed, 9 Feb 2022 14:58:10 GMT, Manukumar V S <mvs at openjdk.org> wrote:

> Create a regression test for [JDK-4670051](https://bugs.openjdk.java.net/browse/JDK-4670051) which checks whether JSpinner with a SpinnerDateModel exactly spins the field where cursor is there.
> I have updated the testing details in the comment section of JDK-8281535.

@aivanov-jdk Can you please review this.

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PR: https://git.openjdk.java.net/jdk/pull/7404