Use QEMU for arm and ppc tests.

Antonio Sánchezrequested to merge
cantonios/eigen:ci into master

The public gitlab aarch64 machines don't seem to like running 32-bit arm tests. Transition though to QEMU.

We've also lost ownership of the PPC gitlab runner, and the runner itself is very out of date. Transition PPC tests to QEMU.

Merge request reports