[Flight] Emit the time we awaited something inside a Server Component (#33402)

Stacked on #33400. 

<img width="1261" alt="Screenshot 2025-06-01 at 10 27 47 PM"
src="https://github.com/user-attachments/assets/a5a73ee2-49e0-4851-84ac-e0df6032efb5"
/>

This is emitted with the start/end time and stack of the "await". Which
may be different than the thing that started the I/O.

These awaits aren't quite as simple as just every await since you can
start a sequence in parallel there can actually be multiple overlapping
awaits and there can be CPU work interleaved with the await on the same
component.

```js
function getData() {
  await fetch(...);
  await fetch(...);
}
const promise = getData();
doWork();
await promise;
```

This has two "I/O" awaits but those are actually happening in parallel
with `doWork()`.

Since these also could have started before we started rendering this
sequence (e.g. a component) we have to clamp it so that we don't
consider awaits that start before the component.

What we're conceptually trying to convey is the time this component was
blocked due to that I/O resource. Whether it's blocked from completing
the last result or if it's blocked from issuing a waterfall request.