Duplicate call GetRegionByID in checkPartitionReplica

[okJiang]

Enhancement

As title, it is unnecessary. The return of GetRegionByID is same as ScanRegions

tidb/pkg/ddl/partition.go

Lines 440 to 451 in cdcc291

	startKey, endKey := tablecodec.GetTableHandleKeyRange(pDef.ID)
	regions, err := pdCli.BatchScanRegions(ctx, []router.KeyRange{{StartKey: startKey, EndKey: endKey}}, -1)
	if err != nil {
	return needWait, errors.Trace(err)
	}
	// For every region in the partition, if it has some corresponding peers and
	// no pending peers, that means the replication has completed.
	for _, region := range regions {
	regionState, err := pdCli.GetRegionByID(ctx, region.Meta.Id)
	if err != nil {
	return needWait, errors.Trace(err)
	}