RFR: 8359257: Create accessibility protocol for TabGroup component [v2]

[Alexander Zuev]

> Create implementation of the TabGroup protocol and assign it to TAB_PANE and PAGINATION roles.

Alexander Zuev has updated the pull request incrementally with one additional commit since the last revision:

  Fixing indentation.

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1823/files
  - new: https://git.openjdk.org/jfx/pull/1823/files/2730768f..1d0bda30

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1823&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1823&range=00-01

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jfx/pull/1823.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1823/head:pull/1823

PR: https://git.openjdk.org/jfx/pull/1823