flaky test in the TestFlashbackSchema

[hawkingrei]

Bug Report

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1. Minimal reproduce step (Required)

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

3. What did you see instead (Required)

    testkit.go:454: 
        	Error Trace:	pkg/testkit/testkit.go:454
        	            				pkg/executor/recover_test.go:580
        	Error:      	Error message not equal:
        	            	expected: "Can't find dropped database: db_not_exists in DDL history jobs"
        	            	actual  : "Can't find dropped database 'db_not_exists' in GC safe point 2024-01-05 17:15:12.298 +0000 UTC"
        	Test:       	TestFlashbackSchema 

https://tiprow.hawkingrei.com/view/gs/pingcapprow/pr-logs/pull/pingcap_tidb/49161/tiprow_fast_test/1744042583610363904#1:build-log.txt%3A8266

4. What is your TiDB version? (Required)