[jdk11u-dev] RFR: 8306566: Open source several clipboard AWT tests

[Antonio Vieiro]

Clean backport of [JDK-8306566](https://bugs.openjdk.org/browse/JDK-8306566) for parity with Oracle 11.0.24

All five tests pass in Linux/Gnome and Windows 11.

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

Commit messages:
 - Backport 136dad7197a1969b2b1fc325f4336c20386c5d3b

Changes: https://git.openjdk.org/jdk11u-dev/pull/2781/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2781&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306566
  Stats: 864 lines in 6 files changed: 864 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2781.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2781/head:pull/2781

PR: https://git.openjdk.org/jdk11u-dev/pull/2781