Retry using different pod when node shutdown.

When node shutdown then the retry pod will always use the same pod
because it can not recongize that the pod can not work anymore and
k8s can not delete it before the node recovered and it will cause
retry is actually not working.

I fix it by check the DeletionTimestamp to know if the pod is actually
not work any more.

Fix tektoncd#6558

Signed-off-by: yuzhipeng <zpyu@alauda.io>

pkg/pod/status.go

@@ -400,7 +400,8 @@ func DidTaskRunFail(pod *corev1.Pod) bool {
 			}
 		}
 	}
-	return false
+	// when the node shutdown the pod will be in Terminating and be deleted
+	return pod.DeletionTimestamp != nil
 }
 
 // IsPodArchived indicates if a pod is archived in the retriesStatus.