Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Move pkg/scheduler/util/testutil.go to pkg/scheduler/testing

**What this PR does / why we need it**:
In the package `k8s.io/kubernetes/pkg/scheduler/util`, we have testutil.go, which has an init() function. Since this package is imported in production code, we are inadvertently running test code in production.

Fortunately (depending on how you look at it) scheduler already has a package called `k8s.io/kubernetes/pkg/scheduler/testing` which would be an appropriate home for these utils.

**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 #63269

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```