Don't run buildx in CI (#19405)
Don't run buildx in CI (#19405)

I suspect this is the root cause of
https://github.com/istio/test-infra/issues/1988

For now, we will revert this and see if things improve
smawson/istio,smawson/istio,smawson/istio,smawson/istio,istio/istio,smawson/istio,istio/istio,istio/istio,istio/istio,istio/istio,smawson/istio