Unstable test TestKillAutoAnalyzeIndex

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftidb%2Fghpr_unit_test/detail/ghpr_unit_test/38831/pipeline

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

### 3. What did you see instead (Required)
```
analyze_test.go:1888:
Error Trace: pkg/executor/test/analyzetest/analyze_test.go:1888
pkg/executor/test/analyzetest/analyze_test.go:2044
pkg/executor/test/analyzetest/analyze_test.go:2047
Error: Not equal:
expected: "failed"
actual : "running"

Diff:
--- Expected
+++ Actual
@@ -1 +1 @@
-failed
+running
Test: TestKillAutoAnalyzeIndex
Messages: kill pending analyze job
```
### 4. What is your TiDB version? (Required)

master