Benching utility for deno_core op system

Example:

```rust use denobenchutil::benchorprofile; use denobenchutil::bencher::{benchmarkgroup, Bencher}; use denobenchutil::benchjs_sync};

use denocore::opsync; use denocore::serializeopresult; use denocore::JsRuntime; use denocore::Op; use denocore::OpState;

fn setup(runtime: &mut JsRuntime) { runtime.registerop("nop", |state, _| { Op::Sync(serializeopresult(Ok(9), state)) }); runtime.syncops_cache(); }

fn benchopnop(b: &mut Bencher) { benchjssync(b, r#"Deno.core.opSync("nop", null, null, null);"#, setup); }

benchmarkgroup!(benches, benchopnop); benchor_profile!(benches); ```