MAP: apply defalut values to the expected object

[naoki9911]

MAP apply default values to the mutated object like below.
This required redundant definition of an expected object.

[internal/tester/testdata/map-object-defaults.test/kaptest.yaml]
[MAP] FAIL: pod-add-label - (CREATE) Pod:base - MUTATE ==> MUTATE
--- Binding:  Param: nil
  &v1.Pod{
        TypeMeta:   {Kind: "Pod", APIVersion: "v1"},
        ObjectMeta: {Name: "base", Namespace: "default", Labels: {"app": "ok-pod", "environment": "test"}},
        Spec: v1.PodSpec{
                Volumes:        nil,
                InitContainers: nil,
                Containers: []v1.Container{
                        {
                                ... // 16 identical fields
                                StartupProbe:             nil,
                                Lifecycle:                nil,
-                               TerminationMessagePath:   "",
+                               TerminationMessagePath:   "/dev/termination-log",
-                               TerminationMessagePolicy: "",
+                               TerminationMessagePolicy: "File",
-                               ImagePullPolicy:          "",
+                               ImagePullPolicy:          "Always",
...

This patch apply defalut values to the expected object, and no more default values are required.

[naoki9911]

Thanks!