DDL integration test is not stable

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

[2023-10-27T08:46:48.364Z] fullstack-test2/ddl/alter_partition_by.test: Running

[2023-10-27T08:46:58.284Z]   File: fullstack-test2/ddl/alter_partition_by.test

[2023-10-27T08:46:58.284Z]   Error line: 171

[2023-10-27T08:46:58.284Z]   Error: select tidb_database,tidb_name from system.tables where tidb_database = 'test' and tidb_name = 't2' and is_tombstone = 0

[2023-10-27T08:46:58.284Z]   Result:

[2023-10-27T08:46:58.284Z]     <nothing>

[2023-10-27T08:46:58.284Z]   Expected:

[2023-10-27T08:46:58.284Z]     ┌─tidb_database─┬─tidb_name─┐

[2023-10-27T08:46:58.284Z]     │ test          │ t2        │

[2023-10-27T08:46:58.284Z]     └───────────────┴───────────┘

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

3. What did you see instead (Required)

4. What is your TiFlash version? (Required)

Run fullstack-test2/ddl/alter_partition_by.test and inspect the failure at line 171, where the query finds no non-tombstone test.t2 table. Trace the DDL and metadata behavior around that check, then verify the integration test reliably observes test.t2 after the partition alteration.