RFR: 8311585: Add JRadioButtonMenuItem to bug8031573.java [v6]

[Alexey Ivanov]

On Fri, 1 Sep 2023 20:44:03 GMT, Rajat Mahajan <rmahajan at openjdk.org> wrote:

>> I have made the test changes to include radio button in menu and tested the same and it works fine.
>
> Rajat Mahajan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update instructions for clarity

Looks good to me.

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Marked as reviewed by aivanov (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15441#pullrequestreview-1607657991