RFR: 8226938: [TEST_BUG]GTK L&F: There is no Details button in FileChooser Dialog

[Abhishek Kumar]

Applet test converted to main based manual test and open sourced.

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Commit messages:
 - Applet test converted to manual and open sourced

Changes: https://git.openjdk.org/jdk/pull/21418/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21418&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8226938
  Stats: 80 lines in 1 file changed: 80 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/21418.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21418/head:pull/21418

PR: https://git.openjdk.org/jdk/pull/21418