Include semantic eval tests for testing performance of API design desicisions on LLM calls

[kiranandcode]

Concrete motivation: If we are injecting things into the system prompt that are severely reducing performance, then we should have tests that would capture this behaviour.

These should be small but domain specific semantic eval tests that check the performance of the effectful LLM api against the actual litellm/openai API.

These should test specific semantic features/functionalities that our downstream projects rely on, for example:

• generating instances of custom classes
• generating terms in effectful sublanguages
• making use of lexical variables, or tools.

etc.

[eb8680]

We might be able to repurpose the intro notebook and many of the simple examples we already have for this as a starting point, e.g. #547 #413 #404

Running these examples in a daily cron job or in CI (though that could get expensive) could go a long way toward catching egregious semantic performance regressions like #567