[BUG] flaky unit test TestRevisionManage

[furykerry]

What happened:
unit test fails sometimes

I0331 08:45:12.439640   29806 uniteddeployment_update.go:110] UnitedDeployment default/foo needs creating subset (StatefulSet) with name: [subset-a]
--- FAIL: TestRevisionManage (4.18s)
    revision_test.go:117: 
        Expected
            <*errors.StatusError | 0xc0001488c0>: {
                ErrStatus: {
                    TypeMeta: {Kind: "", APIVersion: ""},
                    ListMeta: {
                        SelfLink: "",
                        ResourceVersion: "",
                        Continue: "",
                        RemainingItemCount: nil,
                    },
                    Status: "Failure",
                    Message: "Operation cannot be fulfilled on uniteddeployments.apps.kruise.io \"foo\": the object has been modified; please apply your changes to the latest version and try again",
                    Reason: "Conflict",
                    Details: {
                        Name: "foo",
                        Group: "apps.kruise.io",
                        Kind: "uniteddeployments",
                        UID: "",
                        Causes: nil,
                        RetryAfterSeconds: 0,
                    },
                    Code: 409,
                },
            }
        to be nil

What you expected to happen:
test case should be stable

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

Environment:

• Kruise version:
• Kubernetes version (use kubectl version):
• Install details (e.g. helm install args):
• Others: