feat: support multiple connections (sessions) in a single test file

[BugenZhao]

Signed-off-by: Bugen Zhao i@bugenzhao.com

DuckDB's sqllogictest implementation provides the ability for establishing multiple connections in an slt file and specify which to use for each query or statement, which is helpful for testing database transactions.

This PR implements a similar feature, except that we will use a line connection <name> instead of the DuckDB's syntax since it is already utilized by our error matching feature.

This is a breaking change to the interfaces of the library crate (like Runner::new), so maybe we need to bump the minor version under 0.

[BugenZhao]

@wangrunji0408 @xxchan @skyzh Would you please help to review this? 🥰

[BugenZhao]

All comments resolved. Please take a look again. 🥰

[xxchan]

new version published