Function normalize

src/lower2/helpers.rs:379–384

Normalize smaller ints → I32

(ty: &Type)

                    3 => Instruction::Astore_3,
                    _ => unreachable!(),
                }
            } else if index <= u8::MAX as u16 {
                Instruction::Astore(index as u8)
            } else {
                Instruction::Astore_w(index)
            }
        }
        Unit | Void => {
            return Err(jvm::Error::VerificationError {