Better Numerical gadget testing

[huitseeker]

https://github.com/lurk-lab/lurk-rs/pull/563 (https://github.com/lurk-lab/lurk-rs/issues/52) tests our out-of-circuit evaluation logic for Num.

We should review and upgrade similar tests for our gadgets in https://github.com/lurk-lab/lurk-rs/blob/master/src/circuit/gadgets/constraints.rs to test the edge cases of our numerical gadgets. In particular, this should evidence if/when inputs are constrained to be u64.

[jobez]

I can take this.

Per our discussion, my understanding of the task is:

• take in-circuit edge case tests of numerical gadgets like https://github.com/lurk-lab/lurk-rs/blob/ebbbe81cfb9fea4f21a743a49649f94c800cb78b/src/circuit/circuit_frame.rs#L5823-L5881
• expand them to take a larger set of randomizable, composable inputs via (proptest)

[arthurpaulino]

@jobez these can be the target for a first round: https://github.com/lurk-lab/lurk-rs/blob/6d0f79cafca953b8b39d72cf96cbb30a08d24612/src/lem/circuit.rs#L41-L43