RFR: 8325564: ComboBox popup does not correctly resize after update when on display [v3]

[Ziad El Midaoui]

> Fixed popup size not changing to show more items or less when changing the number of items in `ComboBox` by adding a `popupResize` variable which triggers a request layout when there is change in items list.
> Tested with the test app in bug and MonkeyTester.

Ziad El Midaoui has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:

 - Merge branch 'openjdk:master' into 8325564.popupSize
 - Removed 'popupResize' flag
 - Merge branch 'openjdk:master' into 8325564.popupSize
 - Merge branch 'openjdk:master' into 8325564.popupSize
 - Fixed ComboBox popup size not changing after update.

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/2052/files
  - new: https://git.openjdk.org/jfx/pull/2052/files/c975fc59..29a4d177

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=2052&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=2052&range=01-02

  Stats: 1464 lines in 18 files changed: 867 ins; 445 del; 152 mod
  Patch: https://git.openjdk.org/jfx/pull/2052.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/2052/head:pull/2052

PR: https://git.openjdk.org/jfx/pull/2052