folio.yml and replay-ui.yml ran the same operation: build sanderling for
a platform, bring a target up, run a spec against it, classify the trace,
upload the run. They are now one matrix over four examples, each naming
its own runner.
The job is named for what it fuzzes. 'dogfood' named why we run it, not
what runs, the same error as a diagnostic that reports a motivation
instead of an observation.
The matrix is computed by a plan job because jobs.<id>.if cannot read the
matrix context, so a static matrix has no way to leave a leg out. Seeds,
budgets, timeouts, runners and artifact names are unchanged.
