Changed paths:
M syz-cluster/workflow/build-step/Dockerfile
M syz-cluster/workflow/build-step/workflow-template.yaml
M syz-cluster/workflow/triage-step/Dockerfile
M syz-cluster/workflow/triage-step/workflow-template.yaml
Instead of a complicated overlayfs setup, do a lightweight git clone in
a way that the cloned local copy keeps on referencing the git object
storage on the NFS.
It's simpler code-wise and hopefully will be less susceptible to
failures when local git operations coincide with a git fetch on the
shared repository.