Cortex-R52 FVP suite is built but never executed in CI #805

The Cortex-R52 port's FVP suite has never run in CI. r52_fvp.yml builds the default and feature (VFP, FIQ, IRQ and FIQ nesting) configurations and runs CTest when FVP_AEMV8R_URL is set. That variable is unset, so every run logs "built, not executed", and execution results come only from contributors' local runs. With #804, both configurations also build the FVP module example, whose two images are the module isolation tests, and the S32Z280 kernel and module examples, which need silicon and stay build-only.

The blocker is getting the model to a runner. Arm distributes the AEM FVP behind a click-through licence with no stable download URL, so a hosted runner cannot fetch it. A Foundation-hosted runner with the model installed is requested in eclipsefdn/helpdesk#7864, together with ZoneX (eclipse-threadx/zonex#6). A Foundation-hosted mirror to point FVP_AEMV8R_URL at would serve equally well. A project-maintained self-hosted runner is not pursued: every pull request comes from a fork, so its isolation belongs with infrastructure that is somebody's job.

Closing this means r52_fvp.yml executes the default and feature images on every push to dev and master, and on pull requests as far as the runner's isolation allows, with a missing result line still counted as a failure, while contributors without the model keep the build lanes rather than a red cross they cannot act on.

For reference, local runs on the Armv8-R AEM FVP 11.32 with the module example enabled give 8/8 default and 11/11 feature.

Supersedes #668 and #712.