[jdk21u-dev] RFR: 8327969: Convert javax/swing/border/Test6910490.java applet test to main

[Goetz Lindenmaier]

I backport this for parity with 21.0.9-oracle,

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Commit messages:
 - Backport 759cc675915c551cc1d6899eedb95900752f2703

Changes: https://git.openjdk.org/jdk21u-dev/pull/1893/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1893&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8327969
  Stats: 61 lines in 2 files changed: 20 ins; 34 del; 7 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1893.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1893/head:pull/1893

PR: https://git.openjdk.org/jdk21u-dev/pull/1893