RFR: 8306133: Open source few AWT Drag & Drop related tests

[Damon Nguyen]

This PR open sources few AWT DnD related tests

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Commit messages:
 - Open source few DnD AWT tests

Changes: https://git.openjdk.org/jdk/pull/13591/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13591&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306133
  Stats: 1064 lines in 5 files changed: 1064 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/13591.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13591/head:pull/13591

PR: https://git.openjdk.org/jdk/pull/13591