Fix: Include restartable init containers in Pod utilization calc

[azylinski]

What type of PR is this?

/kind bug

What this PR does / why we need it:

Fix pod resources utilization calculation - Include restartable init containers

Similar logic is already in k/k: https://github.com/kubernetes/kubernetes/blob/8453eb0c24ea61794157b451e4442ea570abce45/pkg/controller/podautoscaler/replica_calculator.go#L424

Does this PR introduce a user-facing change?

NONE

[x13n]

Can you clarify what problem this is solving?

[towca]

/assign @towca

[towca]

Can you clarify what problem this is solving?

It's bringing CA util calculations in line with the scheduler. Without it, in some weird cases CA could be underestimating how much of a node's resources a pod is taking. E.g. a pod with containers requesting only 1 CPU, but with an initContainer requesting 7 CPU scheduled on an 8-core Node. CA could scale the node down because it'd calculate the utilization as 1/8, when actually the pod is taking 7/8 of the Node.

[towca]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: azylinski, towca

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