Revert commit a31ca0dc98 and move batch/v2alpha1 tests to separate group in KUBE_TEST_API_VERSIONS

pkg/api/testing/fuzzer.go

@@ -169,6 +169,10 @@ func FuzzerFor(t *testing.T, version unversioned.GroupVersion, src rand.Source)
 				j.ManualSelector = nil
 			}
 		},
+		func(cp *batch.ConcurrencyPolicy, c fuzz.Continue) {
+			policies := []batch.ConcurrencyPolicy{batch.AllowConcurrent, batch.ForbidConcurrent, batch.ReplaceConcurrent}
+			*cp = policies[c.Rand.Intn(len(policies))]
+		},
 		func(j *api.List, c fuzz.Continue) {
 			c.FuzzNoCustom(j) // fuzz self without calling this function again
 			// TODO: uncomment when round trip starts from a versioned object