[jdk11u-dev] RFR: 8041447: Test javax/swing/dnd/7171812/bug7171812.java fails with java.lang.RuntimeException: Test failed, scroll on drag doesn't work

[Amos]

- Backport for [JDK-8041447](https://bugs.openjdk.org/browse/JDK-8041447)
- Tested pass in local

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Commit messages:
 - Backport 2c52cf07469970f730aa7397f9f6b98534af3a44

Changes: https://git.openjdk.org/jdk11u-dev/pull/2159/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2159&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8041447
  Stats: 34 lines in 2 files changed: 20 ins; 4 del; 10 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2159.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2159/head:pull/2159

PR: https://git.openjdk.org/jdk11u-dev/pull/2159