RFR: 8361521 : BogusFocusableWindowState.java fails with StackOverflowError on Linux [v4]

[Anass Baya]

> **Analysis:**
> The getFocusableWindowState() method is not intended to modify the configuration; doing so can cause recursive re-entry on Linux.
> 
> **Proposed Fix:**
> We are intentionally overriding getFocusableWindowState() to allow it to change the configuration, in order to verify that calling getScreenImOn() for ownerless windows does not throw any exceptions.
> To prevent recursive re-entry, we use a flag to ensure that getFocusableWindowState() is executed only once

Anass Baya has updated the pull request incrementally with three additional commits since the last revision:

 - Respect rules
 - remove space
 - Update focusability only when it is needed

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26298/files
  - new: https://git.openjdk.org/jdk/pull/26298/files/f33a7229..489f0734

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26298&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26298&range=02-03

  Stats: 6 lines in 1 file changed: 2 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26298.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26298/head:pull/26298

PR: https://git.openjdk.org/jdk/pull/26298