Make node sorting deterministic as it otherwise causes flakes

[Alexis-D]

All things being equal, compare node names to break ties.

Example flake: https://app.circleci.com/pipelines/github/palantir/k8s-spark-scheduler/1857/workflows/017da816-ce66-4a03-898d-36ddfbe3d850/jobs/6103

Confirmed this works by running the test in a loop:

• with current logic it yields several failures
• with this PR it's all ✅

[svc-autorelease]

Released 0.44.0