scan region retry not work as expected.

[3pointer]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

we had a retry in

tidb/br/pkg/restore/split.go

Lines 108 to 111 in 4e69c07

	if berrors.ErrPDBatchScanRegion.Equal(errScan) {
	log.Warn("inconsistent region info get.", logutil.ShortError(errScan))
	time.Sleep(time.Second)
	continue SplitRegions

, to retry the error in CheckRegionConsistency. but it's not work as expected.
because the multerr is not equal to origin error.
see the test.

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

retry at least 32 * 3 times when region not consistency.

3. What did you see instead (Required)

only 3 times retry.

4. What is your TiDB version? (Required)

master