[jdk11u-dev] RFR: 8256109: Create implementation for NSAccessibilityButton protocol

[Autumn]

Preparing to backport JDK-8256109, Mostly clean, changed the copyright date and fixed some empty line conflicts. This is part of broader group of changes as part of [JDK-8152350](https://bugs.openjdk.org/browse/JDK-8152350).

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Commit messages:
 - 8256109: Create implementation for NSAccessibilityButton protocol

Changes: https://git.openjdk.org/jdk11u-dev/pull/1505/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1505&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8256109
  Stats: 252 lines in 5 files changed: 238 ins; 3 del; 11 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1505.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1505/head:pull/1505

PR: https://git.openjdk.org/jdk11u-dev/pull/1505