Automatic merge from submit-queue

namespace deletion and kubelet restart tests for vSphere cloud provider

**What this PR does / why we need it**:
Following tests for vSphere cloud provider are added as part of this PR

**Test to verifiy that a volume mounted to a pod that is deleted while the kubelet is down,  unmounts volume when the kubelet returns**

**Steps:**
1. Create volume (vmdk)
2. Create PV with volume path for the vmdk.
3. Create PVC to bind with PV.
4. Create a pod using the PVC.
5. Verify disk is attached to the node. and verify volume is mounted on the node.
6. Stop kubelet.
7. Delete pod.
8. Start kubelet.
9. Verify that volume mount not to be found on the node.


**Test to verify that deleting the Namespace of a PVC and Pod causes the successful detach of Persistent Disk.**

**Steps:**
1. Create volume (vmdk)
2. Create PV with volume path for the vmdk.
3. Create PVC to bind with PV.
4. Create a pod using the PVC.
5. Verify disk is attached to the node. 
6. Delete Namespace.
7. Wait for namespace to get deleted. (Namespace deletion should trigger deletion of belonging pods)
8. Verify volume should be detached from the node.


Moved test from https://github.com/kubernetes/kubernetes/pull/41976

**Test to verify that a volume mounted to a pod remains mounted after a kubelet restarts.**

1. Create volume (vmdk)
2. Create PV with volume path for the vmdk.
3. Create PVC to bind with PV.
4. Create a pod using the PVC.
5. Verify disk is attached to the node.
6. Write to the volume
7. Restart kubelet on the node on which pod is provisioned.
8. Verify that written file is accessible after kubelet restart.
9. Delete pod.
10. Delete PV, PVC
11. Wait for VMDK to detach from node.
12. Delete VMDK


**Which issue this PR fixes**
fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

cc: @abrarshivani @BaluDontu @tusharnt @pdhamdhere