Merge pull request #46561 from zhangxiaoyu-zidif/return-nil-e2e

Automatic merge from submit-queue (batch tested with PRs 46561, 46566)

Return nil when err is nil

**What this PR does / why we need it**:
Return nil directly when err is nil

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

hack/e2e.go

@@ -112,7 +112,7 @@ func (t tester) lookKubetest() (string, error) {
 		p := filepath.Join(t.goPath, "bin", "kubetest")
 		_, err := t.stat(p)
 		if err == nil {
-			return p, err
+			return p, nil
 		}
 	}