[jdk11u-dev] RFR: 8256126: Create implementation for NSAccessibilityImage protocol peer

[Autumn Capasso]

clean backport [JDK-8256126](https://bugs.openjdk.org/browse/JDK-8256126) 3 of 28.

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Depends on: https://git.openjdk.org/jdk11u-dev/pull/1571

Commit messages:
 - backport bbb93ca3c80968d4f167bb4cd9e5d3e60e4a6a5b
 - Backport 9d669c912d3977027f321a5e6b7f045ca2ce9482 one of 28. Clean.

Changes: https://git.openjdk.org/jdk11u-dev/pull/1572/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1572&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8256126
  Stats: 86 lines in 4 files changed: 83 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1572.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1572/head:pull/1572

PR: https://git.openjdk.org/jdk11u-dev/pull/1572