This tool can be used across mysql sources.
`mysql-execute-sql` config is as below:
```
tools:
mysql_execute_sql_tool:
kind: "mysql-execute-sql"
source: my-mysql-source
description: Use this tool to execute sql.
```
The `mysql-execute-sql` tool takes one parameter. Example request as
follow:
```
curl -X POST -H "Content-Type: application/json" -d '{"sql": "SELECT 1"}' http://127.0.0.1:5000/api/tool/mysql_execute_sql_tool/invoke
```
Remove cleaning `\\` or `\` in `got` and `want` strings of test cases.
This is to prevent future the need to manually clean strings before
comparing. This also allows us to be aware of the amount of backspace to
prevent accidental escaping in src code.
Update integration test that is affected. This includes moving the
`want` of test cases for `my-param-tool` invocation to each sources
since spanner have a different format (return id as strings instead of
int).
