Check preprocessed traces

[morganthomas]

The verifier needs to check that the prover is sending correct commitments to the preprocessed traces. The prover can send openings, proven with the batch opening proof, which let the verifier check that the commitments to the preprocessed traces are for the correct preprocessed traces. Or maybe the verifier can check it by reproducing the same commitments to the preprocessed traces.

[morganthomas]

In verify_constraints in machine/src/verify.rs, the OpenedValues struct should be populated with the openings of the preprocessed trace polynomials at the random point, as computed by the verifier, as opposed to as claimed by the prover.