RFR: 8286822: Write a test to check the DND functionality between two InternalFrames [v2]

[Manukumar V S]

> This test verifies that dragging from one InternalFrame and a drop target in another InternalFrame functions properly.
> This fix moves an unstable closed applet based test to open regression based java test, but updated to be more comprehensive with some stabilisation improvements. The closed test was creating noise in CI as it often fails in Windows platform, especially in Windows 11.
> 
> Testing:
> 1. Tested using mach5 20 times per platform and got all Pass.
> 2. Tested using mach5 5 times specifically on Windows 11 and got all Pass.

Manukumar V S has updated the pull request incrementally with one additional commit since the last revision:

  Following the process to convert a closed test to open, created a PR in closed space and got it reviewed, now updating this open PR

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8753/files
  - new: https://git.openjdk.java.net/jdk/pull/8753/files/7d00c305..aeb3edb1

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8753&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8753&range=00-01

  Stats: 8 lines in 1 file changed: 0 ins; 4 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8753.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8753/head:pull/8753

PR: https://git.openjdk.java.net/jdk/pull/8753