RFR: 8315677: Open source few swing JFileChooser and other tests

[Abhishek Kumar]

Few closed JFileChooser and other swing tests are open sourced.

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Commit messages:
 - Open source few swing JFileChooser and other tests

Changes: https://git.openjdk.org/jdk/pull/15626/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15626&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315677
  Stats: 358 lines in 5 files changed: 358 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15626.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15626/head:pull/15626

PR: https://git.openjdk.org/jdk/pull/15626