[jdk21u-dev] RFR: 8328379: Convert URLDragTest.html applet test to main

[toshiogata]

Hi all,

I would like to backport this patch to improve test maintainability. The patch is clean.
Testing: manually checked URLDragTest.java, and confirmed that the test works in the same way.

Thank you.

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Commit messages:
 - Merge branch 'master' into JDK-8328379
 - Backport fbeac98c84078a566c572abeba07c49e94bbf26b

Changes: https://git.openjdk.org/jdk21u-dev/pull/1098/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1098&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8328379
  Stats: 227 lines in 3 files changed: 94 ins; 133 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1098.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1098/head:pull/1098

PR: https://git.openjdk.org/jdk21u-dev/pull/1098