RFR: 8277853: With Touch enabled devices scrollbar disappears and the table is scrolled to the beginning [v3]

[meghanEmbrace]

On Tue, 25 Jan 2022 14:34:09 GMT, meghanEmbrace <duke at openjdk.java.net> wrote:

>> With a touch-enabled device, the scrollbar disappears a short while after it's used. During the layout, updateHbar() checks the hbar visibility and resets the clip, causing the user to be scrolled fully to the left when trying to access columns on the right. Using hbar.isVisible() is not feasible as there are times when the scrollbar is necessary but not visible (such as on touch-enabled devices where the scrollbar disappears when not in use, or when hidden by CSS). Hence, it is more reliable to use the variable that determines whether the hbar is necessary.
>
> meghanEmbrace has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Replaced the null test with an assert.

Updated test name to be more descriptive.

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PR: https://git.openjdk.java.net/jfx/pull/688