A Verifier instance is there to verify a class file according to The Java Virtual
Machine Specification, 2nd Edition.
Pass-3b-verification includes pass-3a-verification;
pass-3a-verification includes pass-2-verification;
pass-2-verification includes pass-1-verification.
A Verifier creates PassVerifier instances to perform the actual verification.
Verifier instances are usually generated by the VerifierFactory.
