git: openjdk/jdk21u-dev: master: 8369226: GHA: Switch to MacOS 15

[Aleksey Shipilev]

Changeset: cc434af6
Branch: master
Author:    Aleksey Shipilev <shade at openjdk.org>
Date:      2025-10-27 08:08:10 +0000
URL:       https://git.openjdk.org/jdk21u-dev/commit/cc434af66db9c9d787992569fe1b26074dd495dd

8369226: GHA: Switch to MacOS 15

Reviewed-by: simonis
Backport-of: 1ea8cfa6dc8e6f96fd87553331abaae17ec173ea

! .github/workflows/main.yml