RFR: 8319103: Popups that request focus are not shown on Linux with Wayland [v2]

[Alexander Zvegintsev]

> This is the fix for the regression introduced in [JDK-8280993](https://bugs.openjdk.org/browse/JDK-8280993).
> 
> That fix was to dismiss a popup if the owner loses the window focus when running in Wayland, and didn't take into account that the popup itself can be focusable.
> 
> This fix closes the popup only if the focus moves away from the calling window and the popup itself.
> 
> There is no jtreg test provided because it requires transferring the window focus to a non-X11 window, and our current robot implementation [does not allow this](https://bugs.openjdk.org/browse/JDK-8280983).

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

  manual test added

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/16636/files
  - new: https://git.openjdk.org/jdk/pull/16636/files/0421fedc..06850c0d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16636&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16636&range=00-01

  Stats: 94 lines in 1 file changed: 94 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/16636.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16636/head:pull/16636

PR: https://git.openjdk.org/jdk/pull/16636