DATA RACE in the TestStillWriteConflictAfterRetry

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

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

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

```
==================
WARNING: DATA RACE
Write at 0x00c00b2a48a9 by goroutine 19499:
github.com/tikv/client-go/v2/internal/unionstore/art.(*ART).setValue()
external/com_github_tikv_client_go_v2/internal/unionstore/art/art.go:377 +0x32c
github.com/tikv/client-go/v2/internal/unionstore/art.(*ART).Set()
external/com_github_tikv_client_go_v2/internal/unionstore/art/art.go:124 +0x1b6
github.com/tikv/client-go/v2/internal/unionstore.(*artDBWithContext).set()
external/com_github_tikv_client_go_v2/internal/unionstore/memdb_art.go:51 +0x16e
github.com/tikv/client-go/v2/internal/unionstore.(*artDBWithContext).UpdateFlags()
external/com_github_tikv_client_go_v2/internal/unionstore/memdb_art.go:70 +0x8e
github.com/tikv/client-go/v2/txnkv/transaction.(*KVTxn).lockKeys()
external/com_github_tikv_client_go_v2/txnkv/transaction/txn.go:1547 +0x2c45
github.com/tikv/client-go/v2/txnkv/transaction.(*KVTxn).LockKeysFunc()
external/com_github_tikv_client_go_v2/txnkv/transaction/txn.go:1230 +0x1c6
github.com/pingcap/tidb/pkg/store/driver/txn.(*tikvTxn).LockKeysFunc()
pkg/store/driver/txn/txn_driver.go:106 +0x174
github.com/pingcap/tidb/pkg/session.(*LazyTxn).LockKeysFunc()
pkg/session/txn.go:482 +0x38b
github.com/pingcap/tidb/pkg/session.(*LazyTxn).LockKeys()
pkg/session/txn.go:457 +0x7a
github.com/pingcap/tidb/pkg/executor.doLockKeys()
pkg/executor/select.go:369 +0x30c
github.com/pingcap/tidb/pkg/executor.(*SelectLockExec).Next()
pkg/executor/select.go:298 +0x84e
github.com/pingcap/tidb/pkg/executor/internal/exec.Next()
pkg/executor/internal/exec/executor.go:460 +0x3a8
github.com/pingcap/tidb/pkg/executor/unionexec.(*UnionExec).resultPuller()
pkg/executor/unionexec/union.go:164 +0x98b
github.com/pingcap/tidb/pkg/executor/unionexec.(*UnionExec).initialize.gowrap1()
pkg/executor/unionexec/union.go:117 +0x5d
Previous read at 0x00c00b2a48a9 by goroutine 19498:
github.com/tikv/client-go/v2/internal/unionstore/art.(*ART).Dirty()
external/com_github_tikv_client_go_v2/internal/unionstore/art/art.go:414 +0x57
github.com/tikv/client-go/v2/internal/unionstore.(*artDBWithContext).Dirty()
:1 +0x17
github.com/tikv/client-go/v2/txnkv/transaction.(*KVTxn).IsReadOnly()
external/com_github_tikv_client_go_v2/txnkv/transaction/txn.go:1699 +0x5e
github.com/pingcap/tidb/pkg/store/driver/txn.(*tikvTxn).IsReadOnly()
:1 +0x3e
github.com/pingcap/tidb/pkg/session.(*LazyTxn).IsReadOnly()
:1 +0x46
github.com/pingcap/tidb/pkg/executor.(*PointGetExecutor).get()
pkg/executor/point_get.go:647 +0xfc
github.com/pingcap/tidb/pkg/executor.(*PointGetExecutor).getAndLock()
pkg/executor/point_get.go:560 +0x2bd
github.com/pingcap/tidb/pkg/executor.(*PointGetExecutor).Next()
pkg/executor/point_get.go:393 +0x11cd
github.com/pingcap/tidb/pkg/executor/internal/exec.Next()
pkg/executor/internal/exec/executor.go:460 +0x3a8
github.com/pingcap/tidb/pkg/executor.(*SelectLockExec).Next()
pkg/executor/select.go:247 +0xdb
github.com/pingcap/tidb/pkg/executor/internal/exec.Next()
pkg/executor/internal/exec/executor.go:460 +0x3a8
github.com/pingcap/tidb/pkg/executor/unionexec.(*UnionExec).resultPuller()
pkg/executor/unionexec/union.go:164 +0x98b
github.com/pingcap/tidb/pkg/executor/unionexec.(*UnionExec).initialize.gowrap1()
pkg/executor/unionexec/union.go:117 +0x5d
Goroutine 19499 (running) created at:
github.com/pingcap/tidb/pkg/executor/unionexec.(*UnionExec).initialize()
pkg/executor/unionexec/union.go:117 +0x525
github.com/pingcap/tidb/pkg/executor/unionexec.(*UnionExec).Next()
pkg/executor/unionexec/union.go:190 +0xb9
github.com/pingcap/tidb/pkg/executor/internal/exec.Next()
pkg/executor/internal/exec/executor.go:460 +0x3a8
github.com/pingcap/tidb/pkg/executor/aggregate.(*HashAggExec).fetchChildData()
pkg/executor/aggregate/agg_hash_executor.go:479 +0x2bb
github.com/pingcap/tidb/pkg/executor/aggregate.(*HashAggExec).prepare4ParallelExec.gowrap1()
pkg/executor/aggregate/agg_hash_executor.go:558 +0x5d
Goroutine 19498 (running) created at:
github.com/pingcap/tidb/pkg/executor/unionexec.(*UnionExec).initialize()
pkg/executor/unionexec/union.go:117 +0x525
github.com/pingcap/tidb/pkg/executor/unionexec.(*UnionExec).Next()
pkg/executor/unionexec/union.go:190 +0xb9
github.com/pingcap/tidb/pkg/executor/internal/exec.Next()
pkg/executor/internal/exec/executor.go:460 +0x3a8
github.com/pingcap/tidb/pkg/executor/aggregate.(*HashAggExec).fetchChildData()
pkg/executor/aggregate/agg_hash_executor.go:479 +0x2bb
github.com/pingcap/tidb/pkg/executor/aggregate.(*HashAggExec).prepare4ParallelExec.gowrap1()
pkg/executor/aggregate/agg_hash_executor.go:558 +0x5d
==================
```

https://tiprow.hawkingrei.com/view/gs/pingcapprow/logs/tidb_data_race/1863452190752903168#1:build-log.txt%3A59411

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

Start with TestStillWriteConflictAfterRetry and the linked race log, then trace the reported paths through pkg/executor and the transaction code. Reproduce the test with the race detector and determine the synchronization boundary involved. Done means the test no longer reports this data race.

Written by the indexing model from the issue text.