git: openjdk/jdk21: 8310259: Pin msys2/setup-msys2 github action to a specific commit

[Jaikiran Pai]

Changeset: 08965e64
Author:    Jaikiran Pai <jpai at openjdk.org>
Date:      2023-06-20 01:08:56 +0000
URL:       https://git.openjdk.org/jdk21/commit/08965e646e3aa8caabb5802331c637fed4db1197

8310259: Pin msys2/setup-msys2 github action to a specific commit
8309934: Update GitHub Actions to use JDK 17 for building jtreg

Reviewed-by: cstein, clanger
Backport-of: 959a61fdd483c9523764b9ba0972f59ca06db0ee

! .github/actions/get-jtreg/action.yml
! .github/actions/get-msys2/action.yml