RFR: 8309934: Update GitHub Actions to use JDK 17 for building jtreg

[Martin Doerr]

On Wed, 14 Jun 2023 10:07:01 GMT, Christian Stein <cstein at openjdk.org> wrote:

> Hi all,
> 
> This pull request contains a backport of commit [8aad881e](https://github.com/openjdk/jdk/commit/8aad881e803fddc26f45270f779ff0c0e5a095d8) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.
> 
> The commit being backported was authored by Christian Stein on 13 Jun 2023 and was reviewed by Erik Joelsson.
> 
> Thanks!

Thanks for backporting! Could you enable GitHub Actions and run the tests, please?

-------------

Marked as reviewed by mdoerr (Reviewer).

PR Review: https://git.openjdk.org/jdk21/pull/18#pullrequestreview-1479333689