IS_UUID and UUID_TO_BIN shouldn't trim the argument

[YangKeao]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

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

mysql> SELECT IS_UUID(' 6ccd780c-baba-1026-8567-4cc3505b2a62 ');
+---------------------------------------------------+
| IS_UUID(' 6ccd780c-baba-1026-8567-4cc3505b2a62 ') |
+---------------------------------------------------+
|                                                 0 |
+---------------------------------------------------+
1 row in set (0.03 sec)

mysql> SELECT UUID_TO_BIN(' 6ccd780c-baba-1026-9564-5b8c656024db ');
ERROR 1411 (HY000): Incorrect string value: ' 6ccd780c-baba-1026-9564-5b8c656024db ' for function uuid_to_bin

3. What did you see instead (Required)

mysql> SELECT IS_UUID(' 6ccd780c-baba-1026-8567-4cc3505b2a62 ');
+---------------------------------------------------+
| IS_UUID(' 6ccd780c-baba-1026-8567-4cc3505b2a62 ') |
+---------------------------------------------------+
|                                                 1 |
+---------------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT UUID_TO_BIN(' 6ccd780c-baba-1026-9564-5b8c656024db ');
+--------------------------------------------------------------------------------------------------------------+
| UUID_TO_BIN(' 6ccd780c-baba-1026-9564-5b8c656024db ')                                                        |
+--------------------------------------------------------------------------------------------------------------+
| 0x6CCD780CBABA102695645B8C656024DB                                                                           |
+--------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

4. What is your TiDB version? (Required)

[zanmato1984]

/severity moderate