RFR: 8277785: ListView scrollTo jumps to wrong location when CellHeight is changed [v3]

[Johan Vos]

> 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 test to check if there are no empty cells at the end of a List in case there are enough leading cells available.

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Changes:
  - all: https://git.openjdk.java.net/jfx/pull/712/files
  - new: https://git.openjdk.java.net/jfx/pull/712/files/05935373..a931ba75

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=712&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=712&range=01-02

  Stats: 35 lines in 1 file changed: 35 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/712.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/712/head:pull/712

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