RFR: 8315741: Open source few swing JFormattedTextField and JPopupMenu tests

[Abhishek Kumar]

Few closed JFormattedTextField and JPopupMenu tests are open sourced.

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Commit messages:
 - Open source few swing JFormattedTextField and JPopupMenu tests

Changes: https://git.openjdk.org/jdk/pull/15737/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15737&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315741
  Stats: 486 lines in 5 files changed: 486 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15737.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15737/head:pull/15737

PR: https://git.openjdk.org/jdk/pull/15737