RFR: 8334874: Horizontal scroll events from touch pads should scroll the TabPane tabs [v4]

[Jose Pereda]

> This PR considers the horizontal scroll events that can be generated on a trackpad, on an horizontally sided `TabPane` control (top or bottom), adding to the existing vertical scroll events from mouse wheel and trackpad, to scroll its tabs.
> 
> Therefore, scrolling a `TabPane` will behave in the same way that `ScrollBar` does regarding those same events and control orientation (vertical/horizontal).

Jose Pereda has updated the pull request incrementally with one additional commit since the last revision:

  remove extra new line

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1486/files
  - new: https://git.openjdk.org/jfx/pull/1486/files/2c4914ca..a8969ce8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1486&range=03
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1486&range=02-03

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1486.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1486/head:pull/1486

PR: https://git.openjdk.org/jfx/pull/1486