EvalDuration not support time format in int

[breezewish]

mysql:

mysql> select hour(020005);
Field   1:  `hour(020005)`
Catalog:    `def`
Database:   ``
Table:      ``
Org_table:  ``
Type:       LONGLONG
Collation:  binary (63)
Length:     2
Max_length: 1
Decimals:   0
Flags:      BINARY NUM 


+--------------+
| hour(020005) |
+--------------+
|            2 |
+--------------+
1 row in set (0.00 sec)

tidb:

mysql> select hour(020005);
Field   1:  `hour(020005)`
Catalog:    `def`
Database:   ``
Table:      ``
Org_table:  ``
Type:       LONGLONG
Collation:  binary (63)
Length:     3
Max_length: 0
Decimals:   0
Flags:      BINARY NUM 


+--------------+
| hour(020005) |
+--------------+
|         NULL |
+--------------+
1 row in set (0.00 sec)

@tiancaiamao PTAL