Notice from the n-api docs that the data returned from
`napi_get_typedarray_info` is already adjusted by the byte offset.
https://nodejs.org/api/n-api.html#napi_get_typedarray_info
This means that when `as_ref`/`as_mut` apply the byte offset, the
offset is in practice applied twice.
This wasn't caught in tests because no test tried to modify a typed
array with a byte offset, and the test didn't us the typed array
structs, only `JsTypedArray`. If you want, I can modify the rest of the
functions in examples/napi-compt-mode/src/arraybuffers.rs
and the matching tests, to test all typed arrays.
IMO the `byte_offset` field can be removed entirely from the struct,
but I wanted to submit a minimal PR.
