recover table by job ID would cause panic

[wjhuang2016]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

func (e *DDLExec) executeRecoverTable(s *ast.RecoverTableStmt) error {
	dom := domain.GetDomain(e.Ctx())
	var job *model.Job
	var err error
	var tblInfo *model.TableInfo
	// Let check table first. Related isssue #46296.
	if s.Table != nil {
		job, tblInfo, err = e.getRecoverTableByTableName(s.Table)
	} else {
		job, tblInfo, err = e.getRecoverTableByJobID(s, dom)
	}
	if err != nil {
		return err
	}
	// Check the table ID was not exists.
	tbl, ok := dom.InfoSchema().TableByID(tblInfo.ID)
	if ok {
		return infoschema.ErrTableExists.GenWithStack("Table '%-.192s' already been recover to '%-.192s', can't be recover repeatedly", s.Table.Name.O, tbl.Meta().Name.O)
	}

ErrTableExists uses s.Table, but it's nil in recover table by job ID.

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

N/A

3. What did you see instead (Required)

N/A

4. What is your TiDB version? (Required)

master