CI: Add some portability tests
This is all the Rust Tier 1 targets, except that:
- we exclude amd64 since that's the usual arch
- we only include one Windows platform
Prompted by #2 (closed) and #3 (closed) and discovers a problem on arm64 too.
This is all the Rust Tier 1 targets, except that:
Prompted by #2 (closed) and #3 (closed) and discovers a problem on arm64 too.