Block invalid trigger syntax or fix doltdump parsing

This is invalid syntax for creating a trigger
MySQL:
```sql
mysql> create trigger trig before insert on t for each row begin select 1; end;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'end' at line 1
```

Dolt:
```sql
tmp/main> create table t (i int);
Query OK, 0 rows affected (0.01 sec)
tmp/main*> create trigger trig before insert on t for each row begin select 1; end;
Query OK, 0 rows affected (0.01 sec)
```

This is relevant because it allows us to create doltdumps that can't be imported.
```shell
james@Mac tmp % dolt dump --file-name bad_trigger.sql
Successfully exported data.

james@Mac tmp % cat bad_trigger.sql
CREATE DATABASE IF NOT EXISTS `tmp`; USE `tmp`;
SET FOREIGN_KEY_CHECKS=0;
SET UNIQUE_CHECKS=0;
DROP TABLE IF EXISTS `t`;
CREATE TABLE `t` (
`i` int
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_bin;
create trigger trig before insert on t for each row begin select 1; end;

james@Mac tmp % rm -rf .dolt
james@Mac tmp % dolt init
Successfully initialized dolt data repository.
james@Mac tmp % dolt sql < bad_trigger.sql
error on line 8 for query create trigger trig before insert on t for each row begin select 1
Error parsing SQL:
syntax error at position 67 near '1'
create trigger trig before insert on t for each row begin select 1

```

Reproduce the trigger statement in Dolt, then export it with `dolt dump --file-name bad_trigger.sql` and import the dump with `dolt sql < bad_trigger.sql`. Compare the accepted syntax with MySQL's rejection and inspect the paths handling `CREATE TRIGGER` and dump output. Done means either the invalid trigger is rejected or the generated dump imports successfully.

Written by the indexing model from the issue text.