Auto merge of #101703 - nicholasbishop:bishop-add-uefi-ci-2, r=jyn514

Add QEMU test for x86_64-unknown-uefi

The UEFI targets don't have std support yet, so the normal tests don't work. However, we can compile a simple no-std program and run it under QEMU to at least check that the target compiles, links, and runs.

Tested locally with: `src/ci/docker/run.sh x86_64-uefi`

Author: bors