fetch: body specified in RequestInit should take precedence

While trying to wrap a library using wasm-rquickjs, I noticed the following incorrect behavior:

fetch(
  new Request('https://api.example.com', {
    method: 'POST',
    body: "original"
  }),
  {  body: "overriden" }
)

It should send body as "overriden", however the fetch polyfill currently sends "original" to the endpoint instead.

As per https://developer.mozilla.org/en-US/docs/Web/API/RequestInit

You can also construct a Request with a RequestInit, and pass the Request to a fetch() call along with another RequestInit. If you do this, and the same option is set in both places, then the value passed directly into fetch() is used.

Currently the way how wasm-rquickjs generates the project really helped a bunch, I could manually patch the http.js file here to take options.body if specified and the wrapped library started working correctly!

Start in crates/wasm-rquickjs/skeleton/src/builtin/http.js around line 73, where the fetch polyfill handles Request and RequestInit options. Reproduce the issue with the provided example and verify that the body passed directly to fetch takes precedence over the Request body.