[jdk11u-dev] RFR: 8306060: Open source few AWT Insets related tests

[Antonio Vieiro]

Clean backport of [JDK-8306060](https://bugs.openjdk.org/browse/JDK-8306060) for parity with Oracle 11.0.24.

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

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Commit messages:
 - Backport 9a68d1d952c308c03c29747794d409831008c144

Changes: https://git.openjdk.org/jdk11u-dev/pull/2792/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2792&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306060
  Stats: 270 lines in 4 files changed: 270 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2792.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2792/head:pull/2792

PR: https://git.openjdk.org/jdk11u-dev/pull/2792