RFR: 8348675: TrayIcon tests fails in Ubuntu 24.10 wayland

[Alexander Zvegintsev]

Several TrayIcon tests are trying to click on the system tray icon with Robot using XTest API.

Basically we have the same kind of failures as before, e.g. [JDK-8280990](https://bugs.openjdk.org/browse/JDK-8280990)
>  the reason is this is using XTEST, an X11 protocol which will not work outside of X11.
>
> In other words, the emulated input event reaches the X11 clients, but not the Wayland compositor which is the actual display server but also the X11 window manager in Wayland, the component which is in charge of moving/resizing/stacking the windows. 

I also tested the same tests by clicking manually instead of using the robot, and it works as expected.
So for now, skip those tests on Wayland (and do some minor cleanup).

Testing after modifications is also green.

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

Commit messages:
 - move mouse away from the hot corner
 - skip tests on wayland
 - cleanup

Changes: https://git.openjdk.org/jdk/pull/23329/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23329&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8348675
  Stats: 140 lines in 4 files changed: 71 ins; 8 del; 61 mod
  Patch: https://git.openjdk.org/jdk/pull/23329.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23329/head:pull/23329

PR: https://git.openjdk.org/jdk/pull/23329