infoschema v2 loads all the tables when starts

[Leavrth]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

1. BR restore to cluster so that the table info is cloned.
2. start a TiDB or BR

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

the normal tables are not loaded into memory

3. What did you see instead (Required)

the normal tables are loaded into memory

The loaded table has field "fk_info":[] instead of "fk_info":null.

4. What is your TiDB version? (Required)

master