RFR: 8359127: Amend java/nio/channels/DatagramChannel/PromiscuousIPv6.java to use @requires for OS platform selection [v2]

[Dermot Boyle]

> Replaced programmatic check for the OS platform (which threw a Skipped exception) with JTreg @requires.

Dermot Boyle has updated the pull request incrementally with one additional commit since the last revision:

  Removed unused supportedByPlatform() method definition

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25781/files
  - new: https://git.openjdk.org/jdk/pull/25781/files/e21548b0..6831ea37

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25781&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25781&range=00-01

  Stats: 7 lines in 1 file changed: 0 ins; 7 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/25781.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25781/head:pull/25781

PR: https://git.openjdk.org/jdk/pull/25781