RFR: 8286258: [Accessibility, macOS, VoiceOver] VoiceOver reads the spinner value wrong and sometime partially [v2]

[Alexander Zuev]

> The issue with the announcement of the custom spin boxes is that the text field inside when the value is being changed by the spinbox data model generates some events that are being interpreted by the accessibility subsystem as if text is being actively edited and the system tries to announce it accordingly. In order to stop it from happening we are going to generate correct events and temporarily suppress the text field's methods that reporting the editing-related changes until the actual editing is happened.
> 
> Make embedded text field not to generate random edit-related events;
> Add manual test case;

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

  Restored accidentally damaged copyright header;
  Removed NSAccessibilityAnnouncementRequestedNotification

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Changes:
  - all: https://git.openjdk.org/jdk/pull/29235/files
  - new: https://git.openjdk.org/jdk/pull/29235/files/1626eb27..81648a2e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29235&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29235&range=00-01

  Stats: 2 lines in 2 files changed: 1 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/29235.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29235/head:pull/29235

PR: https://git.openjdk.org/jdk/pull/29235