Automatic merge from submit-queue (batch tested with PRs 56579, 55236, 56512, 56549, 56538). 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>.
security_context_test.go(TestVerifyRunAsNonRoot): remove unused variables
**What this PR does / why we need it**:
This PR removed unused member and related variables from the test.
**Special notes for your reviewer**:
It's better to review this PR in the mode that ignore whitespace-related changes: https://github.com/kubernetes/kubernetes/pull/56579/files?w=1
**Release note**:
```release-note
NONE
```
CC @simo5
The verification function is fixed to check the value of RunAsNonRoot,
not just the existence of it. Also adds unit tests to verify the correct
behavior.