…avior (#38847)
https://github.com/apache/doris/pull/38847
## Proposed changes
There are two issues here. First, the results of casting are
inconsistent between FE and BE .
```
FE
mysql [(none)]>select cast('3.000' as int);
+----------------------+
| cast('3.000' as INT) |
+----------------------+
| 3 |
+----------------------+
mysql [(none)]>set debug_skip_fold_constant = true;
BE
mysql [(none)]>select cast('3.000' as int);
+----------------------+
| cast('3.000' as INT) |
+----------------------+
| NULL |
+----------------------+
```
The second issue is that casting on BE converts '3.0' to null. Here, the
casting logic for FE and BE has been unified
<!--Describe your changes.-->
## Proposed changes
Issue Number: close #xxx
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---------
Co-authored-by: Xinyi Zou <zouxinyi02@gmail.com>
