Fuzzing for `diesel_infer_query`

We would like to fuzz the API's provided by https://github.com/diesel-rs/diesel/tree/main/diesel_infer_query to uncover SQL constructs not covered yet by the provided implementation. We would like to focus on cases of valid SQL there. We are interested in the following cases:

• Hangs or long running inference
• Minimized cases of the API returning IsNull::Unknown for SQL constructs