Auto merge of #123828 - cuviper:cargo-aarch64-gnu, r=Mark-Simulacrum

ci: test cargo on `aarch64-gnu`

Since `aarch64-unknown-linux-gnu` is a tier-1 target, we should also test cargo on it, especially since cargo's own CI doesn't cover this yet. This might have helped us discover #123733 sooner, which is not a cargo problem but was uncovered by a new cargo test (which we'll have to skip for now). Everything else passes in my local run, so at least we'll have a guard against future regressions.