Lean core-lib tests

[maximebuyse]

This PR adds a new test framework allowing to check that the lean core library behaves like it is supposed to.

The tests are defined in rust, checking that a call to a core function's result with concrete params gives the expected concrete value. The rust is tested to validate that the expected values correspond to the behaviour of rust core. The tests are also translated to lean with aeneas, and checked in lean.

This should validate:

• That the core models defined in Rust are correctly translated by Aeneas
• That the manual lean definitions are correct (for primitives or temporary workarounds when aeneas can't extract some rust models)