RFR: 8277785: ListView scrollTo jumps to wrong location when CellHeight is changed [v2]

[Johan Vos]

On Tue, 22 Mar 2022 08:47:42 GMT, Johan Vos <jvos at openjdk.org> wrote:

>> When the size of a ListCell is changed and a scrollTo method is invoked without having a layout calculation in between, the old (wrong) size is used to calculcate the total estimate. This happens e.g. when the size is changed in the `updateItem` method.
>> This PR will immediately resize the cell and sets the new value in the cache containing the cellsizes.
>
> Johan Vos has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add the option to shift all cells down in case the current calculations would lead to empty cells at the end of the view,
>   while there are available cells before the beginning of the view.

There was a problem in ListView, in which cells are shifted down in case there are empty cells being rendered while there are leading cells available. 
I also added a testcase for this that fails before and succeeds after.

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PR: https://git.openjdk.java.net/jfx/pull/712