This PR improves broken k8s tests.
Use exponential backoff on the unstable HTTP path (getting job status sometimes has broken connection from the server. I couldn't really find the relevant logs to figure out why this is happening, unfortunately).
Fix benchmark tests resource leak check. The existing one was broken because the job submission uses 0.001 node IP resource, which means the cluster_resources can never be the same as available resources. I fixed the issue by not checking node IP resources
K8s infra doesn't support instances < 8 CPUs. I used m5.2xlarge instead of xlarge. It will increase the cost a bit, but it wouldn't be very big.
This PR supports the job-based file manager and runner. It will be the backbone of k8s migration.
The PR handles edge cases that originally existed in the old e2e.py job-based runners.