RFR: 8277785: ListView scrollTo jumps to wrong location when CellHeight is changed [v5]

[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:

  Don't recalculate estimated size while doing a layout cycle.
  There are a number of paths possible that first calculate an offset/position,
  and later do a layoutChildren pass. The offset/position calculations (e.g.
  in scrollTo calls) assume a specific estimatedSize. If that size is changed
  between the first call and the layoutChildren logic, the result will not look
  as intended.
  Hence, we should avoid updating the estimated size at the start of the layout
  phase. We can do it safely at the end.
  Thanks to Zeiss and Florian Kirmaier for providing additional tests.

-------------

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/712/files
  - new: https://git.openjdk.java.net/jfx/pull/712/files/2b1b4bdc..aa08ba26

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=712&range=04
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=712&range=03-04

  Stats: 116 lines in 2 files changed: 115 ins; 1 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