RFR: 8306681: Open source more AWT DnD related tests [v2]

[Damon Nguyen]

> This PR open sources more AWT DnD related tests

Damon Nguyen has updated the pull request incrementally with one additional commit since the last revision:

  Add endline

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13674/files
  - new: https://git.openjdk.org/jdk/pull/13674/files/d0ff637f..c750dde5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13674&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13674&range=00-01

  Stats: 7 lines in 6 files changed: 0 ins; 1 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/13674.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13674/head:pull/13674

PR: https://git.openjdk.org/jdk/pull/13674