Merge pull request #48001 from yguo0905/report-prefix

Automatic merge from submit-queue (batch tested with PRs 47675, 48001)

Encodes ReportPrefix into the generated metrics file names

Ref: https://github.com/kubernetes/kubernetes/issues/44003

Adds the test prefix to be part of the name. Otherwise the same test case running on different images will override each other. Nothing needs to be changed at the node-perf-dash side.

See test run at https://console.cloud.google.com/storage/browser/ygg-gke-dev-bucket/e2e-node-test/ci-kubernetes-node-kubelet-benchmark/10.


**Release note**:
```
None
```

/sig node
/area node-e2e
/assign @Random-Liu

test/e2e_node/benchmark_util.go

@@ -43,7 +43,7 @@ const (
 // data for the test into the file with the specified prefix.
 func dumpDataToFile(data interface{}, labels map[string]string, prefix string) {
 	testName := labels["test"]
-	fileName := path.Join(framework.TestContext.ReportDir, fmt.Sprintf("%s-%s.json", prefix, testName))
+	fileName := path.Join(framework.TestContext.ReportDir, fmt.Sprintf("%s-%s-%s.json", prefix, framework.TestContext.ReportPrefix, testName))
 	labels["timestamp"] = strconv.FormatInt(time.Now().UTC().Unix(), 10)
 	framework.Logf("Dumping perf data for test %q to %q.", testName, fileName)
 	if err := ioutil.WriteFile(fileName, []byte(framework.PrettyPrintJSON(data)), 0644); err != nil {