RFR: JDK-8340713 : Open source DnD tests - Set5

[Harshitha Onkar]

Following tests are open-sourced:

1. /java/awt/dnd/DragExitBeforeDropTest.java - Automated, Problemlisted on macOS
2. /java/awt/dnd/DragThresholdTest.java - Automated, Problemlisted on macOS
3. /java/awt/dnd/WinMoveFileToShellTest.java - Manual, Windows only test

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Commit messages:
 - extra newline
 - problemlist updated
 - DnD test - Set5

Changes: https://git.openjdk.org/jdk/pull/21340/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21340&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8340713
  Stats: 524 lines in 4 files changed: 524 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/21340.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21340/head:pull/21340

PR: https://git.openjdk.org/jdk/pull/21340