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>.

scheduler: update tests to use sub-benchmarks (pkg/scheduler/cache)

**What this PR does / why we need it**:

Go 1.7 added the subtest feature which can make table-driven tests much easier to run and debug. Some tests are not using this feature.

Further reading: [Using Subtests and Sub-benchmarks](https://blog.golang.org/subtests)

/kind cleanup

**Release note**:

```release-note
NONE
```