Restore Txn: client get stuck after restoration.

[3pointer]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

1. tiup playground --db=0 --tiflash=0
2. using tcl(https://github.com/c4pt0r/tcli/tree/main) to write some data
3. run backup txn
4. using tcl(https://github.com/c4pt0r/tcli/tree/main) to delete the data
5. run restore txn
6. using tcl(https://github.com/c4pt0r/tcli/tree/main) to scan

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

scan return directly

3. What did you see instead (Required)

scan gets stuck

4. What is your TiDB version? (Required)

master