RFR: 8301312: Create implementation of NSAccessibilityButton protocol [v6]

[Alexander Zuev]

> Add the common base component for all the new implementing native classes Change native peer creation to use the new base component The new code will instantiate new protocol implementation  for the given role if it exists or an old one if it does not exist
> Added BUTTON role implementing class

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

  Changing performAction parameter to NSString

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1084/files
  - new: https://git.openjdk.org/jfx/pull/1084/files/29cb4b2c..0064c7d7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1084&range=05
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1084&range=04-05

  Stats: 3 lines in 2 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jfx/pull/1084.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1084/head:pull/1084

PR: https://git.openjdk.org/jfx/pull/1084