After drop a table, there is a chance that tiflash's count result is not stable using some read tso. But tikv's result is stable as the following image shows.

The main test process is as follows:

1. start a transaction in some thread.
2. drop the target table and create a table with the same name in another thread.
3. write data into the new table.
4. check the count result of tikv and tiflash in the previous transaction and compare the results.