flaky case TestPiTRCreateNonUniqueIndex

[D3Hunter]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

see https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftidb%2Fghpr_check2/detail/ghpr_check2/2848/pipeline/786/

    workload.go:135: 
        	Error Trace:	tests/realtikvtest/addindextestutil/workload.go:135
        	            				tests/realtikvtest/addindextestutil/common.go:387
        	Error:      	Received unexpected error:
        	            	[global:2]execution result undetermined
        	            	github.com/pingcap/errors.AddStack
        	            		external/com_github_pingcap_errors/errors.go:174
        	            	github.com/pingcap/errors.Trace
        	            		external/com_github_pingcap_errors/juju_adaptor.go:15
        	            	github.com/pingcap/tidb/pkg/testkit.(*TestKit).ExecWithContext
        	            		pkg/testkit/testkit.go:382
        	            	github.com/pingcap/tidb/pkg/testkit.(*TestKit).Exec
        	            		pkg/testkit/testkit.go:337
        	            	github.com/pingcap/tidb/tests/realtikvtest/addindextestutil.deleteWorker
        	            		tests/realtikvtest/addindextestutil/workload.go:234
        	            	github.com/pingcap/tidb/tests/realtikvtest/addindextestutil.(*worker).run
        	            		tests/realtikvtest/addindextestutil/workload.go:107
        	            	runtime.goexit
        	            		src/runtime/asm_amd64.s:1650
        	Test:       	TestPiTRCreateNonUniqueIndex

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

3. What did you see instead (Required)

4. What is your TiDB version? (Required)