vmm_tests: openhcl pcat vms hang on amd machines

[tjones60]

OpenHCL PCAT tests are hanging on our AMD test runners. This happens primarily on Windows VMs, where the Windows logo is present along with a pinwheel that keeps spinning, but the VM never boots.

[chris-oo]

one idea is maybe we should have openhcl inject an NMI on a test timeout, then wait for that to finish before we terminate to help debug these