Wrong behavior on builtin function truncate

[winoros]

Please answer these questions before submitting your issue. Thanks!

1. What did you do?
   If possible, provide a recipe for reproducing the error.

select truncate(9223372036854775808, -10);

TiDB don't handle the unsigned int case of this function.

2. What did you expect to see?

+------------------------------------+
| truncate(9223372036854775808, -10) |
+------------------------------------+
|                9223372030000000000 |
+------------------------------------+

3. What did you see instead?

mysql> select truncate(9223372036854775808, -10);
+------------------------------------+
| truncate(9223372036854775808, -10) |
+------------------------------------+
|                9223372043709551616 |
+------------------------------------+
1 row in set (0.00 sec)

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

master branch 129f499

[winoros]

closed since duplicated with #7591