Merge pull request kubernetes#58354 from msau42/fix-e2e-nfs-scale

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Change default volume source to regular emptydir for e2e volume servers

**What this PR does / why we need it**:
Use regular emptydir instead of tmpfs emptydir in e2es to avoid hitting default memory limits.

**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 kubernetes#58280

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

test/e2e/framework/volume_util.go

@@ -244,7 +244,7 @@ func StartVolumeServer(client clientset.Interface, config VolumeTestConfig) *v1.
 		mountName := fmt.Sprintf("path%d", i)
 		volumes[i].Name = mountName
 		if src == "" {
-			volumes[i].VolumeSource.EmptyDir = &v1.EmptyDirVolumeSource{Medium: v1.StorageMediumMemory}
+			volumes[i].VolumeSource.EmptyDir = &v1.EmptyDirVolumeSource{}
 		} else {
 			volumes[i].VolumeSource.HostPath = &v1.HostPathVolumeSource{
 				Path: src,