ChenPeng2013/tidb: store/helper/helper.go; 22 LoC

Found a possible issue in [ChenPeng2013/tidb](https://www.github.com/ChenPeng2013/tidb) at [store/helper/helper.go](https://github.com/ChenPeng2013/tidb/blob/047dfddf27d48dc7ca3336f5f863d70b91626265/store/helper/helper.go#L203-L224)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first issue it finds, so please do not limit your consideration to the contents of the below message.

> reference to regionMetric was used in a composite literal at line 204

[Click here to see the code in its original context.](https://github.com/ChenPeng2013/tidb/blob/047dfddf27d48dc7ca3336f5f863d70b91626265/store/helper/helper.go#L203-L224)

Click here to show the 22 line(s) of Go which triggered the analyzer.

```go
for regionID, regionMetric := range metrics {
t := HotTableIndex{RegionID: regionID, RegionMetric: ®ionMetric}
region, err := h.RegionCache.LocateRegionByID(tikv.NewBackofferWithVars(context.Background(), 500, nil), regionID)
if err != nil {
logutil.BgLogger().Error("locate region failed", zap.Error(err))
continue
}

hotRange, err := NewRegionFrameRange(region)
if err != nil {
return nil, err
}
f := h.FindTableIndexOfRegion(allSchemas, hotRange)
if f != nil {
t.DbName = f.DBName
t.TableName = f.TableName
t.TableID = f.TableID
t.IndexName = f.IndexName
t.IndexID = f.IndexID
}
hotTables = append(hotTables, t)
}

```

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commit ID: 047dfddf27d48dc7ca3336f5f863d70b91626265