Add 64-bit Arm (Graviton) as a supported platform

[SeanTAllen]

We have CI for 64-bit Arm via Graviton. We know that at least
on the 64-bit Raspberry Pi that there are still issues.

[ponylang-main]

Hi @SeanTAllen,

The changelog - added label was added to this pull request; all PRs with a changelog label need to have release notes included as part of the PR. If you haven't added release notes already, please do.

Release notes are added by creating a uniquely named file in the .release-notes directory. We suggest you call the file 3876.md to match the number of this pull request.

The basic format of the release notes (using markdown) should be:

## Title

End user description of changes, why it's important,
problems it solves etc.

If a breaking change, make sure to include 1 or more
examples what code would look like prior to this change
and how to update it to work after this change.

Thanks.

[SeanTAllen]

The windows failure is one of our "its flakey" issues we've been having with the TCP tests with Windows lately.

[SeanTAllen]

Realized that I don't have the builder files included in this.