Automatic merge from submit-queue (batch tested with PRs 53567, 53197, 52944, 49593). 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>.

Refactor network policy e2e tests, and add additional logging when tests fail

**What this PR does / why we need it**:
- Restructure tests, clean up duplicate code
- Add additional logging, so it's easier to debug when the tests fail
- Add retry on the client side pods because sometimes kubelet will start the pod when the network is not ready, resulting in flaky tests
- Add readiness probe for the server pods to further reduce the flakiness.

Current failure messages when a test fails:
```
checking client-can-connect could communicate with server.
  Expected error:
      <*errors.errorString | 0xc420868820>: {
          s: "pod \"client-can-connect\" failed with status: {Phase:Failed Conditions:[{Type:Initialized Status:True LastProbeTime:0001-01-01 00:00:00 +0000 UTC LastTransitionTime:2017-07-25 15:54:48 -0700 PDT Reason: Message:} {Type:Ready Status:False LastProbeTime:0001-01-01 00:00:00 +0000 UTC LastTransitionTime:2017-07-25 15:54:57 -0700 PDT Reason:ContainersNotReady Message:containers with unready status: [client-can-connect-container]} {Type:PodScheduled Status:True LastProbeTime:0001-01-01 00:00:00 +0000 UTC LastTransitionTime:2017-07-25 15:54:48 -0700 PDT Reason: Message:}] Message: Reason: HostIP:10.138.0.2 PodIP:10.60.1.180 StartTime:2017-07-25 15:54:48 -0700 PDT InitContainerStatuses:[] ContainerStatuses:[{Name:client-can-connect-container State:{Waiting:nil Running:nil Terminated:&ContainerStateTerminated{ExitCode:1,Signal:0,Reason:Error,Message:,StartedAt:2017-07-25 15:54:49 -0700 PDT,FinishedAt:2017-07-25 15:54:57 -0700 PDT,ContainerID:docker://c91c33139672c20a5231bcba9437d74e12d35a6d19275b41bb8e571148b4ab57,}} LastTerminationState:{Waiting:nil Running:nil Terminated:nil} Ready:false RestartCount:0 Image:gcr.io/google_containers/redis:e2e ImageID:docker://sha256:e5e67996c442f903cda78dd983ea6e94bb4e542950fd2eba666b44cbd303df42 ContainerID:docker://c91c33139672c20a5231bcba9437d74e12d35a6d19275b41bb8e571148b4ab57}] QOSClass:BestEffort}",
      }
      pod "client-can-connect" failed with status: {Phase:Failed Conditions:[{Type:Initialized Status:True LastProbeTime:0001-01-01 00:00:00 +0000 UTC LastTransitionTime:2017-07-25 15:54:48 -0700 PDT Reason: Message:} {Type:Ready Status:False LastProbeTime:0001-01-01 00:00:00 +0000 UTC LastTransitionTime:2017-07-25 15:54:57 -0700 PDT Reason:ContainersNotReady Message:containers with unready status: [client-can-connect-container]} {Type:PodScheduled Status:True LastProbeTime:0001-01-01 00:00:00 +0000 UTC LastTransitionTime:2017-07-25 15:54:48 -0700 PDT Reason: Message:}] Message: Reason: HostIP:10.138.0.2 PodIP:10.60.1.180 StartTime:2017-07-25 15:54:48 -0700 PDT InitContainerStatuses:[] ContainerStatuses:[{Name:client-can-connect-container State:{Waiting:nil Running:nil Terminated:&ContainerStateTerminated{ExitCode:1,Signal:0,Reason:Error,Message:,StartedAt:2017-07-25 15:54:49 -0700 PDT,FinishedAt:2017-07-25 15:54:57 -0700 PDT,ContainerID:docker://c91c33139672c20a5231bcba9437d74e12d35a6d19275b41bb8e571148b4ab57,}} LastTerminationState:{Waiting:nil Running:nil Terminated:nil} Ready:false RestartCount:0 Image:gcr.io/google_containers/redis:e2e ImageID:docker://sha256:e5e67996c442f903cda78dd983ea6e94bb4e542950fd2eba666b44cbd303df42 ContainerID:docker://c91c33139672c20a5231bcba9437d74e12d35a6d19275b41bb8e571148b4ab57}] QOSClass:BestEffort}
  not to have occurred
```

Failure message with this PR:
```
 should support a 'default-deny' policy [Feature:NetworkPolicy] [It]
    /Users/gunjan/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/test/e2e/network/network_policy.go:81

    Jul 25 14:35:55.978: Pod client-cannot-connect should be able to connect to service svc-server, but was not able to connect.
    Pod logs:
    Connecting to svc-server.e2e-tests-network-policy-tbzm8:80 (10.63.254.124:80)
    wget: download timed out
    Connecting to svc-server.e2e-tests-network-policy-tbzm8:80 (10.63.254.124:80)
    wget: download timed out
    Connecting to svc-server.e2e-tests-network-policy-tbzm8:80 (10.63.254.124:80)
    wget: download timed out
    Connecting to svc-server.e2e-tests-network-policy-tbzm8:80 (10.63.254.124:80)
    wget: download timed out
    Connecting to svc-server.e2e-tests-network-policy-tbzm8:80 (10.63.254.124:80)
    wget: download timed out


   Current NetworkPolicies:
    	[{{ } {deny-all  e2e-tests-network-policy-tbzm8 /apis/networking.k8s.io/v1/namespaces/e2e-tests-network-policy-tbzm8/networkpolicies/deny-all 20fa92ab-7181-11e7-855b-42010a8a0003 87694 1 2017-07-25 14:35:07 -0700 PDT <nil> <nil> map[] map[] [] nil [] } {{map[] []} []}}]

   Pods:
    	[Pod: server, Status: &PodStatus{Phase:Running,Conditions:[{Initialized True 0001-01-01 00:00:00 +0000 UTC 2017-07-25 14:34:52 -0700 PDT  } {Ready True 0001-01-01 00:00:00 +0000 UTC 2017-07-25 14:35:00 -0700 PDT  } {PodScheduled True 0001-01-01 00:00:00 +0000 UTC 2017-07-25 14:34:52 -0700 PDT  }],Message:,Reason:,HostIP:10.138.0.2,PodIP:10.60.1.145,StartTime:2017-07-25 14:34:52 -0700 PDT,ContainerStatuses:[{server-container-80 {nil ContainerStateRunning{StartedAt:2017-07-25 14:34:53 -0700 PDT,} nil} {nil nil nil} true 0 gcr.io/google_containers/porter:4524579c docker://sha256:711ccbc1c74f3417f2a0f403c194017b3bde09eec3c3b42dc9c838db3894c223 docker://3fa73da57380ef28520f8bbf53b3540f523ab76d45a1b42cc9a1e4573eb45639}],QOSClass:BestEffort,InitContainerStatuses:[],}
     Pod: server, Status: &PodStatus{Phase:Running,Conditions:[{Initialized True 0001-01-01 00:00:00 +0000 UTC 2017-07-25 14:34:52 -0700 PDT  } {Ready True 0001-01-01 00:00:00 +0000 UTC 2017-07-25 14:35:00 -0700 PDT  } {PodScheduled True 0001-01-01 00:00:00 +0000 UTC 2017-07-25 14:34:52 -0700 PDT  }],Message:,Reason:,HostIP:10.138.0.2,PodIP:10.60.1.145,StartTime:2017-07-25 14:34:52 -0700 PDT,ContainerStatuses:[{server-container-80 {nil ContainerStateRunning{StartedAt:2017-07-25 14:34:53 -0700 PDT,} nil} {nil nil nil} true 0 gcr.io/google_containers/porter:4524579c docker://sha256:711ccbc1c74f3417f2a0f403c194017b3bde09eec3c3b42dc9c838db3894c223 docker://3fa73da57380ef28520f8bbf53b3540f523ab76d45a1b42cc9a1e4573eb45639}],QOSClass:BestEffort,InitContainerStatuses:[],}
    ]
```
**Release note**:

```release-note
NONE
```