2 Changes in this CL:
## Support multiple statements in one request like:
```
select 10; select 20; select 30;
```
ISSUE: #3049
For simple testing this CL, you can using mysql-client shell command tools:
```
mysql> delimiter //
mysql> select 1; select 2; //
+------+
| 1 |
+------+
| 1 |
+------+
1 row in set (0.01 sec)
+------+
| 2 |
+------+
| 2 |
+------+
1 row in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
```
I add a new class called `OriginStatement.java`, to save the origin statement in string format with an index. This class is mainly for the following cases:
1. User send a multi-statement to the non-master FE:
`DDL1; DDL2; DDL3`
2. Currently we cannot separate the original string of a single statement from multiple statements. So we have to forward the entire statement to the Master FE. So I add an index in the forward request. `DDL1`'s index is 0, `DDL2`'s index is 1,...
3. When the Master FE handle the forwarded request, it will parse the entire statement, got 3 DDL statements, and using the `index` to get the specified the statement.
## Optimized the display of syntax errors
I have also optimized the display of syntax errors so that longer syntax errors can be fully displayed.
4c98596283