RFR: 8306464: [testbug] CustomSecurityManagerTest full screen tests fails on MacOS intermittently [v3]

[Karthik P K]

> Usage of `getBounds()` method instead `getVisualBounds()` was giving unreliable screen bound values and color value was read very close to the edge of the window.
> 
> Updated the code to use `getVisualBounds()` instead of `getBounds()` and moved the coordinates inside the window from where the color value is read.
> 
> Ran the tests individually and along with all system tests in following systems. No failure found after the fix.
> Mac M1 with Ventura 13.3
> Window 11

Karthik P K has updated the pull request incrementally with one additional commit since the last revision:

  Adress review comments

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1103/files
  - new: https://git.openjdk.org/jfx/pull/1103/files/32b18089..faf55390

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1103&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1103&range=01-02

  Stats: 9 lines in 1 file changed: 0 ins; 6 del; 3 mod
  Patch: https://git.openjdk.org/jfx/pull/1103.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1103/head:pull/1103

PR: https://git.openjdk.org/jfx/pull/1103