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

[Alexey Ivanov]

On Thu, 25 Dec 2025 08:10:07 GMT, Sergey Bylokhov <serb at openjdk.org> wrote:

> 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`

Marked as reviewed by aivanov (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/28991#pullrequestreview-3621054295