feat: add equivalence tests

[DavePearce]

These constraints are taken from Consensys/corset#241 and should be added as tests:

(defcolumns X)

(defconstraint constraint-1 () (is-not-zero! (if (is-zero 1) 1 1)))
(defconstraint constraint-2 () (eq! (is-not-zero! (if (is-zero X) 1 X)) 0))
(defconstraint constraint-3 () (eq! (~and! (is-not-zero! (if (is-zero 0) 1 0)) 0) 0))
(defconstraint constraint-4 () (is-not-zero! (if (is-zero 0) 1 0)))
(defconstraint constraint-5 () (is-not-zero! (if (is-zero X) 1 X)))

(module module-0)
(defcolumns in0 ST)
(defconstraint constraint-0 () (if-not-zero ST (vanishes! (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) (~and! 1 1)))))
(defconstraint constraint-1 () (if-not-zero ST (vanishes! (if (is-zero (~or! (if (is-zero 1) 0 0) (if (is-zero 1) 0 0))) (if (is-zero in0) in0 0) (~and! 1 1)))))
(defconstraint constraint-2 () (if-not-zero ST (vanishes! (is-not-zero! (is-not-zero! (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) (~and! 1 1)))))))
(defconstraint constraint-3 () (if-not-zero ST (vanishes! (~or! (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) (~and! 1 1)) 1))))
(defconstraint constraint-4 () (if-not-zero ST (vanishes! (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) 1))))
(defconstraint constraint-5 () (if-not-zero ST (vanishes! (~and! (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) (~and! 1 1)) (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) (~and! 1 1))))))

(module module-1)
(defcolumns in0 ST)
(defconstraint constraint-0 () (if-not-zero ST (vanishes! (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) (~and! 1 1)))))
(defconstraint constraint-1 () (if-not-zero ST (vanishes! (if (is-zero (~or! (if (is-zero 1) 0 0) (if (is-zero 1) 0 0))) (if (is-zero in0) in0 0) (~and! 1 1)))))
(defconstraint constraint-2 () (if-not-zero ST (vanishes! (is-not-zero! (is-not-zero! (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) (~and! 1 1)))))))
(defconstraint constraint-3 () (if-not-zero ST (vanishes! (~or! (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) (~and! 1 1)) 1))))
(defconstraint constraint-4 () (if-not-zero ST (vanishes! (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) 1))))
(defconstraint constraint-5 () (if-not-zero ST (vanishes! (~and! (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) (~and! 1 1)) (if (is-zero (if (is-zero 1) 0 0)) (if (is-zero in0) in0 0) (~and! 1 1))))))