Benching utility for deno_core op system

Example:

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

use deno_core::Extension;

[op]

fn op_nop() -> usize { 9 }

fn setup() -> Vec { vec![Extension { name: "myext" ops: std::borrow::Cow::Borrowed(&[opnop::DECL]) }] }

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

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