unstable test TestAuditLogReservedDays

[hawkingrei]

Bug Report

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

3. What did you see instead (Required)

    sysvar_test.go:364: 
        	Error Trace:	extension/enterprise/audit/sysvar_test.go:364
        	Error:      	Should not be: "/home/jenkins/.tidb/tmp/63a9840cd0739f2c243bb46478607469/sandbox/linux-sandbox/7067/execroot/__main__/bazel-out/k8-fastbuild/bin/extension/enterprise/audit/audit_test_/audit_test.runfiles/__main__/extension/enterprise/audit/tidb-audit-2023-05-16T16-01-19.786.log"
        	Test:       	TestAuditLogReservedDays
        	Messages:   	/home/jenkins/.tidb/tmp/63a9840cd0739f2c243bb46478607469/sandbox/linux-sandbox/7067/execroot/__main__/bazel-out/k8-fastbuild/bin/extension/enterprise/audit/audit_test_/audit_test.runfiles/__main__/extension/enterprise/audit/tidb-audit-2023-05-16T16-01-19.786.log /home/jenkins/.tidb/tmp/63a9840cd0739f2c243bb46478607469/sandbox/linux-sandbox/7067/execroot/__main__/bazel-out/k8-fastbuild/bin/extension/enterprise/audit/audit_test_/audit_test.runfiles/__main__/extension/enterprise/audit/tidb-audit-2023-05-16T16-01-19.786.log

https://do.pingcap.net/jenkins/blue/rest/organizations/jenkins/pipelines/pingcap/pipelines/tidb/pipelines/ghpr_unit_test/runs/24584/nodes/59/steps/64/log/?start=0

4. What is your TiDB version? (Required)