dillon1000/react

[Fizz] Don't double replay elements when it's the postpone point (#27440)

The `resumeElement` function wasn't actually doing the correct thing
because it was resuming the element itself but what the child slot means
is that we're supposed to resume in the direct child of the element.
This is difficult to check for since it's all the possible branches that
the element can render into, so instead we just check this in
renderNode. It means the hottest path always checks the task which is
unfortunate.

And also, resuming using the correct nextSegmentId.

Fixes two bugs surfaced by this test.

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Co-authored-by: Josh Story <[email protected]>