[Dynamic Regions] split-table flag in TiDB should be disabled when partitioned raft kv is enabled

[tonyxuqqi]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

tikv/tikv#15269

1. enable partitioned raft kv
2. create table
3. SPLIT TABLE %s BETWEEN (0) AND (1000000000) REGIONS %d
4. execute insert into %s values%s", tableName, valuesStr) in each region

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

Pass

3. What did you see instead (Required)

Failure

4. What is your TiDB version? (Required)

7.4

It's kind of by design that partitioned raft kv cannot support many regions per TiKV and also even if it can support 10K more regions, the performance would be pretty bad. The split-table in general is not appropriate for partitioned raft kv.