query TIDB_HOT_REGIONS return some unexpected result

[crazycs520]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

related issue: #50809

select * from `TIDB_HOT_REGIONS`;

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

the query result don't contain any system memory table, since memory table doesn't have any data in tikv regions.

3. What did you see instead (Required)

The query result contain some system memory table.

+---------------------+----------+--------------------+------------------------+------------+-----------+------+----------------+--------------+------------+
| TABLE_ID            | INDEX_ID | DB_NAME            | TABLE_NAME             | INDEX_NAME | REGION_ID | TYPE | MAX_HOT_DEGREE | REGION_COUNT | FLOW_BYTES |
+---------------------+----------+--------------------+------------------------+------------+-----------+------+----------------+--------------+------------+
| 4611686018427387996 | <null>   | INFORMATION_SCHEMA | TIDB_CHECK_CONSTRAINTS | <null>     | 52        | read | 87             | 0            | 31200      |
| 104                 | 0        | test               | t1                     | PRIMARY    | 14        | read | 86             | 0            | 230161     |
+---------------------+----------+--------------------+------------------------+------------+-----------+------+----------------+--------------+------------+

4. What is your TiDB version? (Required)

+-----------------------------------------------------------+
| tidb_version()                                            |
+-----------------------------------------------------------+
| Release Version: v8.0.0-alpha-143-g7087f70                |
| Edition: Community                                        |
| Git Commit Hash: 7087f702e18f811c98d5a276eace7bb69292c6aa |
| Git Branch: HEAD                                          |
| UTC Build Time: 2024-01-30 03:53:25                       |
| GoVersion: go1.21.4                                       |
| Race Enabled: false                                       |
| Check Table Before Drop: false                            |
| Store: tikv                                               |
+-----------------------------------------------------------+