Automatic merge from submit-queue (batch tested with PRs 50536, 50809, 50220, 50399, 50176)
Refactor statefulset test with sets.String
**What this PR does / why we need it**:
Delete redundant sort. These string slices only own one element.
There is no necessary to sort them.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
The alpha field podManagementPolicy defines how pods are created,
deleted, and replaced. The new `Parallel` policy will replace pods
as fast as possible, not waiting for the pod to be `Ready` or providing
an order. This allows for advanced clustered software to take advantage
of rapid changes in scale.
1. pcb and pcb controller are removed and their functionality is
encapsulated in StatefulPodControlInterface.
2. IdentityMappers has been removed to clarify what properties of a Pod are
mutated by the controller. All mutations are performed in the
UpdateStatefulPod method of the StatefulPodControlInterface.
3. The statefulSetIterator and petQueue classes are removed. These classes
sorted Pods by CreationTimestamp. This is brittle and not resilient to
clock skew. The current control loop, which implements the same logic,
is in stateful_set_control.go. The Pods are now sorted and considered by
their ordinal indices, as is outlined in the documentation.
4. StatefulSetController now checks to see if the Pods matching a
StatefulSet's Selector also match the Name of the StatefulSet. This will
make the controller resilient to overlapping, and will be enhanced by
the addition of ControllerRefs.