Fixed compile-time error in spv fuzzer test. (#967)

* Fixed compile-time error in spv fuzzer test.

error[E0061]: this function takes 2 arguments but 1 argument was supplied
   --> fuzz_targets/spv_parser.rs:7:19
    |
7   |     let _result = Parser::new(data.into_iter()).parse();
    |                   ^^^^^^^^^^^ ---------------- supplied 1 argument
    |                   |
    |                   expected 2 arguments
    |
note: associated function defined here
   --> /Users/evgeny.proydakov/repository/naga/src/front/spv/mod.rs:411:12
    |
411 |     pub fn new(data: I, options: &Options) -> Self {
    |            ^^^

error: aborting due to previous error

* Code review. Group imports