RFR: 8081507: Open or Save button in JFileChooser has OK title in GTK LaF

[Tejesh R]

On Tue, 27 Dec 2022 19:05:10 GMT, Abhishek Kumar <abhiscxk at openjdk.org> wrote:

> Open or Save button in JFileChooser has OK title in GTK LAF. The open/save button text modified as per the native FileChooser. Manual test case is added.
> 
> `open/test/jdk/sanity/client/SwingSet/src/FileChooserDemoTest.java` failed with the current fix with an exception `**Wait AbstractButton with text "OK" loaded.**` Updated the test for GTK LAF and tested in CI which is OK now.
> 
> CI link is added in JBS.

Fix is tested and working fine.

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Marked as reviewed by tr (Committer).

PR: https://git.openjdk.org/jdk/pull/11790