cas: remove unused simulator removal funcs

[jackfrancis]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

This PR removes two funcs in the Cluster Autoscaler simulator code that are no longer called anywhere (except UT, which are also cleaned up).

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

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[jackfrancis]

/assign @x13n

Do you know whether or not these exportable methods are used downstream? Is there any reason not to delete them?

[elmiko]

seems reasonable to me if they are unused.

[jackfrancis]

gentle ping @x13n

[x13n]

Turns out we use FindNodesToRemove in GKE internal fork, but we should probably just move it there - it just wraps the SimulateNodeRemoval function which is public anyway. FindEmptyNodesToRemove is unused as far as I can tell. Btw, while checking this I also found unused ScaleDownFindNodesToRemove const in metrics.go that should probably also be dropped.

[x13n]

/lgtm
/hold

Putting on hold in case you want to delete ScaleDownFindNodesToRemove in the same PR.

[k8s-ci-robot]

New changes are detected. LGTM label has been removed.

[jackfrancis]

/label tide/merge-method-squash

[jackfrancis]

@x13n thank you, removed ScaleDownFindNodesToRemove as well.

FYI I audited metrics/metrics.go and found that ScaleDownMiscOperations is similarly unused. If you can confirm we can clean that up as well I can make one more change, otherwise feel free to unhold.

thx!

[x13n]

Good catch, I think ScaleDownMiscOperations can be deleted as well.