Remove optimization from getWork in resourcequota/controller.go

[MikeSpreitzer]

What this PR does / why we need it:
This change simplifies the code in
plugin/pkg/admission/resourcequota/controller.go by removing the
optimization in getWork that required the caller to NOT call
completeWork if getWork returns the empty list of work. BTW, the
caller was not obeying that requirement; now the caller's behavior
(which is unchanged) is right.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #63608

Special notes for your reviewer:
This is a simpler alternative to #64377

Release note:

Fixed issue 63608, which is that under rare circumstances the ResourceQuota admission controller could lose track of an request in progress and time out after waiting 10 seconds for a decision to be made.

[MikeSpreitzer]

/test pull-kubernetes-bazel-test

[MikeSpreitzer]

/assign @derekwaynecarr

[dims]

LGTM 👍

[deads2k]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: deads2k, MikeSpreitzer

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[deads2k]

Sorry I missed this. Let's try for the first fix-pack.

[BenTheElder]

/test pull-kubernetes-kubemark-e2e-gce-big

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/retest
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[k8s-github-robot]

Automatic merge from submit-queue (batch tested with PRs 65152, 65199, 65179, 64598, 65216). If you want to cherry-pick this change to another branch, please follow the instructions here.