flaky test at the TestApplyKVFilesWithBatchMethod3

[hawkingrei]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

=== RUN   TestApplyKVFilesWithBatchMethod3

    client_test.go:1399: 

        	Error Trace:	/home/jenkins/.tidb/tmp/63a9840cd0739f2c243bb46478607469/sandbox/linux-sandbox/14306/execroot/__main__/bazel-out/k8-fastbuild/bin/br/pkg/restore/restore_test_/restore_test.runfiles/__main__/br/pkg/restore/client_test.go:1399

        	Error:      	Not equal: 

        	            	expected: [][]string{[]string{"log2"}, []string{"log5", "log6"}, []string{"log4"}, []string{"log3"}, []string{"log1"}}

        	            	actual  : [][]string{[]string{"log2"}, []string{"log5", "log6"}, []string{"log3"}, []string{"log4"}, []string{"log1"}}

        	            	

        	            	Diff:

        	            	--- Expected

        	            	+++ Actual

        	            	@@ -9,6 +9,6 @@

        	            	  ([]string) (len=1) {

        	            	-  (string) (len=4) "log4"

        	            	+  (string) (len=4) "log3"

        	            	  },

        	            	  ([]string) (len=1) {

        	            	-  (string) (len=4) "log3"

        	            	+  (string) (len=4) "log4"

        	            	  },

        	Test:       	TestApplyKVFilesWithBatchMethod3

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

3. What did you see instead (Required)

4. What is your TiDB version? (Required)

[hawkingrei]

https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftidb%2Fghpr_unit_test/detail/ghpr_unit_test/7587/pipeline

it is still in existed.

[hawkingrei]

@joccau PTAL