RFR: 8303130: Document required Accessibility permissions on macOS [v2]

[Dmitry Markov]

> Added the section devoted to client UI test which use Robot API

Dmitry Markov has updated the pull request incrementally with one additional commit since the last revision:

  Fix review findings

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12772/files
  - new: https://git.openjdk.org/jdk/pull/12772/files/1774d37a..e1ec5f9e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12772&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12772&range=00-01

  Stats: 40 lines in 2 files changed: 8 ins; 0 del; 32 mod
  Patch: https://git.openjdk.org/jdk/pull/12772.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12772/head:pull/12772

PR: https://git.openjdk.org/jdk/pull/12772