Automatic merge from submit-queue (batch tested with PRs 62460, 64480, 63774, 64540, 64337). 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>.

use subtest for table units (pkg/master)

**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. Many table-driven tests in pkg/kubectl are not using this feature.

/kind cleanup

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

**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 #

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```