realtikvtest/flashbacktest always failed

[Defined2014]

Bug Report

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1. Minimal reproduce step (Required)

After #52285, flashbacktest alwayws failed with error info like

[r="assert failed, schemaID should not be 0, please set it when creating the event"]
[stack="[github.com/pingcap/tidb/pkg/util.Recover](http://github.com/pingcap/tidb/pkg/util.Recover)
	/home/genius/project/src/[github.com/pingcap/tidb/pkg/util/misc.go:118](http://github.com/pingcap/tidb/pkg/util/misc.go:118)
runtime.gopanic
	/home/genius/project/go/src/runtime/panic.go:914
[github.com/pingcap/tidb/pkg/util/intest.doPanic](http://github.com/pingcap/tidb/pkg/util/intest.doPanic)
	/home/genius/project/src/[github.com/pingcap/tidb/pkg/util/intest/assert.go:59](http://github.com/pingcap/tidb/pkg/util/intest/assert.go:59)
[github.com/pingcap/tidb/pkg/util/intest.Assert](http://github.com/pingcap/tidb/pkg/util/intest.Assert)
	/home/genius/project/src/[github.com/pingcap/tidb/pkg/util/intest/assert.go:27](http://github.com/pingcap/tidb/pkg/util/intest/assert.go:27)
[github.com/pingcap/tidb/pkg/statistics/handle/util.(*DDLEvent).IsMemOrSysDB](http://github.com/pingcap/tidb/pkg/statistics/handle/util.(*DDLEvent).IsMemOrSysDB)
	/home/genius/project/src/[github.com/pingcap/tidb/pkg/statistics/handle/util/ddl_event.go:51](http://github.com/pingcap/tidb/pkg/statistics/handle/util/ddl_event.go:51)
[github.com/pingcap/tidb/pkg/statistics/handle/ddl.(*ddlHandlerImpl).HandleDDLEvent](http://github.com/pingcap/tidb/pkg/statistics/handle/ddl.(*ddlHandlerImpl).HandleDDLEvent)
	/home/genius/project/src/[github.com/pingcap/tidb/pkg/statistics/handle/ddl/ddl.go:58](http://github.com/pingcap/tidb/pkg/statistics/handle/ddl/ddl.go:58)
[github.com/pingcap/tidb/pkg/domain.(*Domain).updateStatsWorker](http://github.com/pingcap/tidb/pkg/domain.(*Domain).updateStatsWorker)
	/home/genius/project/src/[github.com/pingcap/tidb/pkg/domain/domain.go:2415](http://github.com/pingcap/tidb/pkg/domain/domain.go:2415)
[github.com/pingcap/tidb/pkg/domain.(*Domain).UpdateTableStatsLoop.func3](http://github.com/pingcap/tidb/pkg/domain.(*Domain).UpdateTableStatsLoop.func3)
	/home/genius/project/src/[github.com/pingcap/tidb/pkg/domain/domain.go:2235](http://github.com/pingcap/tidb/pkg/domain/domain.go:2235)
[github.com/pingcap/tidb/pkg/util.(*WaitGroupEnhancedWrapper).Run.func1](http://github.com/pingcap/tidb/pkg/util.(*WaitGroupEnhancedWrapper).Run.func1)
	/home/genius/project/src/[github.com/pingcap/tidb/pkg/util/wait_group_wrapper.go:99](http://github.com/pingcap/tidb/pkg/util/wait_group_wrapper.go:99)"]

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

3. What did you see instead (Required)

4. What is your TiDB version? (Required)