flaky test TestKillAutoAnalyzeIndex

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

```
analyze_test.go:1874:

Error Trace: pkg/executor/test/analyzetest/analyze_test.go:1874

pkg/executor/test/analyzetest/analyze_test.go:2027

pkg/executor/test/analyzetest/analyze_test.go:2030

Error: Not equal:

expected: "[executor:1317]Query execution was interrupted"

actual : "runtime error: invalid memory address or nil pointer dereference"

Diff:

--- Expected

+++ Actual

@@ -1 +1 @@

-[executor:1317]Query execution was interrupted

+runtime error: invalid memory address or nil pointer dereference

Test: TestKillAutoAnalyzeIndex

Messages: kill pending analyze job
```

```
[2024/03/21 04:27:17.568 +00:00] [ERROR] [exec.go:65] ["auto analyze failed"] [category=stats] [sql="analyze table `test`.`t` index `idx`"] [cost_time=5.920899ms] [error="runtime error: invalid memory address or nil pointer dereference"] [stack="github.com/pingcap/tidb/pkg/statistics/handle/autoanalyze/exec.AutoAnalyze\n\tpkg/statistics/handle/autoanalyze/exec/exec.go:65\ngithub.com/pingcap/tidb/pkg/statistics/handle/autoanalyze/priorityqueue.(*NonPartitionedTableAnalysisJob).analyzeIndexes\n\tpkg/statistics/handle/autoanalyze/priorityqueue/non_partitioned_table_analysis_job.go:184\ngithub.com/pingcap/tidb/pkg/statistics/handle/autoanalyze/priorityqueue.(*NonPartitionedTableAnalysisJob).Analyze.func1\n\tpkg/statistics/handle/autoanalyze/priorityqueue/non_partitioned_table_analysis_job.go:81\ngithub.com/pingcap/tidb/pkg/statistics/handle/util.CallWithSCtx\n\tpkg/statistics/handle/util/util.go:103\ngithub.com/pingcap/tidb/pkg/statistics/handle/autoanalyze/priorityqueue.(*NonPartitionedTableAnalysisJob).Analyze\n\tpkg/statistics/handle/autoanalyze/priorityqueue/non_partitioned_table_analysis_job.go:76\ngithub.com/pingcap/tidb/pkg/statistics/handle/autoanalyze/refresher.(*Refresher).PickOneTableAndAnalyzeByPriority\n\tpkg/statistics/handle/autoanalyze/refresher/refresher.go:105\ngithub.com/pingcap/tidb/pkg/statistics/handle/autoanalyze.HandleAutoAnalyze\n\tpkg/statistics/handle/autoanalyze/autoanalyze.go:284\ngithub.com/pingcap/tidb/pkg/statistics/handle/autoanalyze.(*statsAnalyze).HandleAutoAnalyze.func1\n\tpkg/statistics/handle/autoanalyze/autoanalyze.go:240\ngithub.com/pingcap/tidb/pkg/statistics/handle/util.CallWithSCtx\n\tpkg/statistics/handle/util/util.go:103\ngithub.com/pingcap/tidb/pkg/statistics/handle/autoanalyze.(*statsAnalyze).HandleAutoAnalyze\n\tpkg/statistics/handle/autoanalyze/autoanalyze.go:239\npkg/executor/test/analyzetest/analyzetest_test.TestKillAutoAnalyzeIndex.func2\n\tpkg/executor/test/analyzetest/analyze_test.go:2018\npkg/executor/test/analyzetest/analyzetest_test.TestKillAutoAnalyzeIndex\n\tpkg/executor/test/analyzetest/analyze_test.go:2030\ntesting.tRunner\n\tGOROOT/src/testing/testing.go:1595"]
```

https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftidb%2Fghpr_unit_test/detail/ghpr_unit_test/6388/pipeline

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

### 3. What did you see instead (Required)

### 4. What is your TiDB version? (Required)

Automated flaky test report update.

Repo: pingcap/tidb
Branch: master
Package: pkg/executor/test/analyzetest
Case: TestKillAutoAnalyzeIndex
Flaky Count: 1
Time Thresholded Count: 0
Latest Build: https://prow.tidb.net/jenkins/job/pingcap/job/tidb/job/merged_unit_test/383/
Window: 2026-06-18T00:00:00.000Z → 2026-06-19T00:00:00.000Z
Threshold: 100000 ms