ci: use spike from core-v-verif (!1538) · Merge requests · OpenHW Group / backup-20241120 / cva6

Created by: cathales

Spike is being moved back to core-v-verif. So now fetching core-v-verif is needed to build spike in CI.

This PR additionally enables VCS environment to build spike, to prepare the CI for the tandem feature.

ci: use spike from core-v-verif