TestTransferPrimary is flaky

[okJiang]

Flaky Test

Which jobs are failing

TestTransferPrimary

    testutil.go:67: 
        	Error Trace:	/home/runner/work/pd/pd/pkg/utils/testutil/testutil.go:67
        	            				/home/runner/work/pd/pd/tests/integrations/mcs/members/member_test.go:216
        	Error:      	Condition never satisfied
        	Test:       	TestMemberTestSuite/TestTransferPrimary

CI link

https://github.com/tikv/pd/actions/runs/10382810965/job/28746541172?pr=8516

Reason for failure (if possible)

Anything else

[okJiang]

https://github.com/tikv/pd/actions/runs/10483277108/job/29035723709?pr=8516

    member_test.go:213: 
        	Error Trace:	/home/runner/work/pd/pd/tests/integrations/mcs/members/member_test.go:213
        	Error:      	Not equal: 
        	            	expected: 200
        	            	actual  : 503
        	Test:       	TestMemberTestSuite/TestTransferPrimary