RFR: 8193547: Regression automated test '/open/test/jdk/java/awt/Toolkit/DesktopProperties/rfe4758438.java' fails

[Alexander Zvegintsev]

This test has multiple issues:

* Test actually does nothing and passes as it is right now, but tests nothing
* `pgrep gnome-session` may return multiple PIDs -> picking up only first one 
* looks like jtreg does not pass GNOME_DESKTOP_SESSION_ID variable(it is deprecated, BTW), so used `XDG_CURRENT_DESKTOP` instead
* removed leftovers from Solaris support
* `org.gnome.settings-daemon.peripherals.mouse` is [deprecated](https://gitlab.gnome.org/GNOME/gnome-settings-daemon/-/blob/master/data/org.gnome.settings-daemon.peripherals.gschema.xml.in#L46) and does not work on latest systems  <br> but newer `org.gnome.desktop.peripherals.mouse` works as expected<br>So the test modified to try new one and to check deprecated as a fallback

CI testing looks good.

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Commit messages:
 - fix access rights
 - initial

Changes: https://git.openjdk.org/jdk/pull/11127/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11127&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8193547
  Stats: 125 lines in 3 files changed: 72 ins; 22 del; 31 mod
  Patch: https://git.openjdk.org/jdk/pull/11127.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11127/head:pull/11127

PR: https://git.openjdk.org/jdk/pull/11127