[jdk17u-dev] RFR: 8306943: Open source several dnd AWT tests

[Victor Rudometov]

Backport of https://github.com/openjdk/jdk/commit/2adb3b409e8cc87685a4379be3f7beeb53706e2e 
https://bugs.openjdk.org/browse/JDK-8306943 Open source several dnd AWT tests

Clean backport, new tests
Checked on macOS x64, linux x64

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Commit messages:
 - Backport 2adb3b409e8cc87685a4379be3f7beeb53706e2e

Changes: https://git.openjdk.org/jdk17u-dev/pull/1351/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1351&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306943
  Stats: 1349 lines in 5 files changed: 1349 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1351.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1351/head:pull/1351

PR: https://git.openjdk.org/jdk17u-dev/pull/1351