This contains the history of this target. Core is built with
cargo build --release -Zbuild-std=core. This checks that
codegen/linking of core works, but does not check whether std builds.
std is being built with cargo miri setup. If a target does
not support std, the std column represents core/alloc. This checks that
std builds (on targets that have it) but does not check whether
codegen/linking works.