Query to `is.tables` is slow in infoschema cache v2

[tangenta]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

1. Create a TiDB cluster that has a lot of schemas and tables.
2. Execute select * from information_schema.tables where table_name = 'xx'

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

It should complete fast.

3. What did you see instead (Required)

It takes about 400ms to finish a query. From the CPU profile, we can see there are many cache misses.

4. What is your TiDB version? (Required)

e16613d

[tangenta]

executor.getAutoIncrementID() should not trigger loadTableInfo().