The Location in the DDL job is empty after decoding.

[zimulala]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Because the Job.Location object's fields are all lowercase, there are no useful fields after json decoding.

	job := &Job{
...
		ReorgMeta: &DDLReorgMeta{
			Location: time.Now().In(time.UTC).Location(),
		},
	}

job.Encode(false)
newJob := &Job{}
err = newJob.Decode(b)

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

Hopefully, it has data innewJob.ReorgMeta.Location.

3. What did you see instead (Required)

No data.

4. What is your TiDB version? (Required)

Release Version: v5.4.0-alpha-571-g7f8509169
Edition: Community
Git Commit Hash: 7f85091
Git Branch: master
UTC Build Time: 2021-12-31 00:08:39

[github-actions]

Please check whether the issue should be labeled with 'affects-x.y' or 'fixes-x.y.z', and then remove 'needs-more-info' label.