br 8.1 CI test failed

[RidRisR]

There are two errors:

1. In br_check_dup_table test, the log shows:
   Error: 'ErrTableAlreadyExisted' not found in logs.

2. In br_pitr_long_running_schema_loading test, the log shows:
   /root/hanzhen/tidb/br/tests/br_pitr_long_running_schema_loading/run.sh: line 45:
   /root/hanzhen/tidb/br/tests/br_pitr_long_running_schema_loading/../br_test_utils.sh: No such file or directory
   The log checkpoint didn't advance to correct timestamp