Improve frequent loops when only one of activities is productive

[macsko]

What type of PR is this?

/kind feature

What this PR does / why we need it:

In a single iteration of the autoscaler, only one of the activities can occur alternately: scaling up or processing ProvisioningRequests. If the activity is productive (scale up happened or ProvisioningRequest was processed), the next iteration is started immediately. Unfortunately, if there is only successful processing of ProvisioningRequests without scaling up activity, the autoscaler will be put to sleep unnecessarily. This PR changes the logic slightly to compare not with the start of the last iteration, but with the previous to the last, to support alternate activities well.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Improved frequent loops when there is only one of scale up activity or ProvisioningRequest processing is productive.

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

[macsko]

/cc @aleksandra-malinowska

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: macsko
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