RFR: 8287740 NSAccessibilityShowMenuAction not working for text editors [v2]

[Artem Semenov]

> The NSAccessibilityShouMinuAction action does not show the menu for the text element. 
> Steps to reproduce: 
> 1. redefine the accessible context with the addition of the toggle popup action; 
> 2. run on macOS with VoiceOver enabled; 
> 3. try to call the context menu in the editor by pressing vo+shift+m.
> 
> @azuev-java please review.

Artem Semenov has updated the pull request incrementally with one additional commit since the last revision:

  Just a small nit, can we use the same style of instructions, the previous tests use a separate text to press the VO shortcuts, here it could be something like this:
  "Turn screen reader on and press Tab to move to the text area"
  "Perform the VO action "Open a shortcut menu" (VO+Shift+m)\n\n"

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8997/files
  - new: https://git.openjdk.java.net/jdk/pull/8997/files/50601c12..5f217525

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8997&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8997&range=00-01

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8997.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8997/head:pull/8997

PR: https://git.openjdk.java.net/jdk/pull/8997