Unstable test TestUpgradeWithPauseDDL

[lance6716]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

found in CI. because I can pass this test in my local environment, I think it's a failure of master branch

https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftidb%2Fghpr_unit_test/detail/ghpr_unit_test/12704/pipeline/

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

3. What did you see instead (Required)

    bootstrap_upgrade_test.go:818: 
        	Error Trace:	pkg/session/bootstraptest/bootstrap_upgrade_test.go:818
        	Error:      	"450910225860395008" is not greater than "450910225874026496"
        	Test:       	TestUpgradeWithPauseDDL
        	Messages:   	test sql:alter table test.pause_user_ddl_t add column c_28 int, ts:450910225860395008, mysql sql:alter table mysql.pause_user_ddl_t add index idx_30(a), ts:450910225874026496

4. What is your TiDB version? (Required)

[lance6716]

After merging master, my PR will also failed in local 😂

[lance6716]

https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftidb%2Fghpr_unit_test/detail/ghpr_unit_test/12649/pipeline

    bootstrap_upgrade_test.go:818: 

        	Error Trace:	pkg/session/bootstraptest/bootstrap_upgrade_test.go:818

        	Error:      	"450905904269754368" is not greater than "450905904272900097"

        	Test:       	TestUpgradeWithPauseDDL

        	Messages:   	test sql:alter table test.pause_user_ddl_t1 add index idx_29(a), ts:450905904269754368, mysql sql:alter table mysql.pause_user_ddl_t add index idx_30(a), ts:450905904272900097

it's a flaky test since #54419 . I can found the failure in its CI