[jdk21u-dev] RFR: 8315742: Open source several Swing Scroll related tests

[Goetz Lindenmaier]

I backport this for parity with 21.0.8-oracle.

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Commit messages:
 - Backport f0ff001dd7db33eb492f01cfa08b11705956ebcd

Changes: https://git.openjdk.org/jdk21u-dev/pull/1469/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1469&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315742
  Stats: 418 lines in 6 files changed: 418 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1469.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1469/head:pull/1469

PR: https://git.openjdk.org/jdk21u-dev/pull/1469