[DevTools] Don't attach filtered IO to grandparent Suspense

[eps1lon]

Fixes "We are cleaning up async info that was not on the parent Suspense boundary." when filtering some Suspense instances e.g.

<Activity name="a">
  <div>
    <Activity name="b">
      <Suspense>
        {promise}

filtering everything below <Activity name="b"> would add the promise to the suspended by of <Activity name="b"> since that's the nearest unfiltered instance. At the same time we'd add the promise to the filtered Suspense node. Once we unmount <Activity name="b">, we'd attempt to remove the promise from its parent Suspense but that never held the promise.

As an alternative, we'd have to move the parentSuspenseNode pointer after we moved the parentInstance pointer. That can be confusing because it's not actually IO that will suspend the Suspense node. Especially if we implement Activity slices with a filter, we'd end up moving IO to the initial paint of an Activity slice even though that IO would be handled further down.