Whether the intermediate state setting of alter constraint is appropriate

[zimulala]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

When we using alter constraint to switch from not enforced to enforced, we may not see the constraint information when executing show create table.

tidb/ddl/constraint.go

Lines 216 to 242 in 052c17f

	if enforced {
	originalState := constraintInfo.State
	switch constraintInfo.State {
	case model.StatePublic:
	job.SchemaState = model.StateWriteReorganization
	constraintInfo.State = model.StateWriteReorganization
	constraintInfo.Enforced = enforced
	ver, err = updateVersionAndTableInfoWithCheck(d, t, job, tblInfo, originalState != constraintInfo.State)
	case model.StateWriteReorganization:
	job.SchemaState = model.StateWriteOnly
	constraintInfo.State = model.StateWriteOnly
	ver, err = updateVersionAndTableInfoWithCheck(d, t, job, tblInfo, originalState != constraintInfo.State)
	case model.StateWriteOnly:
	err = w.verifyRemainRecordsForCheckConstraint(dbInfo, tblInfo, constraintInfo, job)
	if err != nil {
	if !table.ErrCheckConstraintViolated.Equal(err) {
	return ver, errors.Trace(err)
	}
	constraintInfo.Enforced = !enforced
	}
	constraintInfo.State = model.StatePublic
	ver, err = updateVersionAndTableInfoWithCheck(d, t, job, tblInfo, originalState != constraintInfo.State)
	if err != nil {
	return ver, errors.Trace(err)
	}
	job.FinishTableJob(model.JobStateDone, model.StatePublic, ver, tblInfo)
	}

2. What did you expect to see? (Required)

see the constraint information

3. What did you see instead (Required)

may not see the constraint information

4. What is your TiDB version? (Required)

master
After #44455

[zimulala]

PTAL @fzzf678