RFR: 8325194: GHA: Add macOS M1 testing [v5]

[Christoph Langer]

On Sat, 3 Feb 2024 21:55:25 GMT, George Adams <gdams at openjdk.org> wrote:

>> Now that macOS M1 executors are [available in GitHub actions](https://github.blog/changelog/2024-01-30-github-actions-introducing-the-new-m1-macos-runner-available-to-open-source/) it makes sense to move the build to run on M1 (rather than cross-compiled) and also enable testing on the platform.
>
> George Adams has updated the pull request incrementally with one additional commit since the last revision:
> 
>   simplify jtreg

Looks good to me now. But please let another build group member give give their blessing before integrating.

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Marked as reviewed by clanger (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17694#pullrequestreview-1861592810