RFR: 8374355: Update copyright year to 2025 for demo in files where it was missed

[Sergey Bylokhov]

The copyright year in demo files updated in 2025 has been bumped to 2025.

The next command can be run (on top of this PR) to verify that each file had prior commits in 2025:

`git diff HEAD~1 --name-only | while read f; do git log HEAD~1 --since="2025-01-01" --oneline -- "$f" | head -1 | grep -q . || echo "NOT IN 2025: $f"; done`

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Commit messages:
 - 8374355: Update copyright year to 2025 for demo in files where it was missed

Changes: https://git.openjdk.org/jdk/pull/28991/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28991&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8374355
  Stats: 9 lines in 9 files changed: 0 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/28991.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28991/head:pull/28991

PR: https://git.openjdk.org/jdk/pull/28991