[jdk21u-dev] RFR: 8327826: Convert javax/swing/border/Test4243289.java applet test to main

[Goetz Lindenmaier]

I backport this for parity with 21.0.9-oracle

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Commit messages:
 - Backport a43c3cc3476f18c048809bcd08f81fc4288ca399

Changes: https://git.openjdk.org/jdk21u-dev/pull/2006/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2006&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8327826
  Stats: 69 lines in 2 files changed: 24 ins; 33 del; 12 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/2006.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/2006/head:pull/2006

PR: https://git.openjdk.org/jdk21u-dev/pull/2006