[infra] Migrate ChromeOS devices to arm64 RPIs

This is similar to https://skia-review.googlesource.com/c/skia/+/447177

Change-Id: I9189c6994ee02360115f5397d5008e2eb4c3e40e
Bug: skia:12401
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/451916
Reviewed-by: Eric Boren <borenet@google.com>
5 files changed