timeout option has no effect if set on Request

I assume the following 2 `fetch` invocations should behave identically, i.e. both should throw a `TimeoutError`:

A: Passing url and options directly to `fetch()`:
```javascript
const resp = await fetch('https://httpbin.org/delay/5', { timeout: 1000 });
```

B: Passing url and options via `Request` instance to `fetch()`:
```javascript
const req = new Request('https://httpbin.org/delay/5', { timeout: 1000 });
const resp = await fetch(req);
```

A throws a `TimeoutError` as expected. B OTOH ignores the `timeout` option and succeeds.

Start by reproducing the two fetch examples in the issue, comparing direct options with a Request instance. Trace how fetch reads timeout from each entry point; done means both forms reject with a TimeoutError when the delayed URL exceeds the timeout.

Written by the indexing model from the issue text.