br:if restore use checkpoint and user cannot write to storage, br failed too slow

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)
1. br restore full
2. use checkpoint
3. user cannot write to remote storage

### 2. What did you expect to see? (Required)
1. br checked write permission and quickly failed
### 3. What did you see instead (Required)
1. br failed after several minutes
### 4. What is your TiDB version? (Required)
master