Intended behavior: https://github.com/reactwg/react-18/discussions/31

Sandbox: https://codesandbox.io/s/react-18-layouteffect-semantics-forked-m02w5

Expected: when suspended content is hidden and then shown, we get layout cleanup followed by layout setup.
Actual: only layout cleanup happens.


subtreeRoot: Fiber,
  root: FiberRoot,
  committedLanes: Lanes,
) {
  
  const isModernRoot = (subtreeRoot.mode & ConcurrentMode) !== NoMode;
  while (nextEffect !== null) {
    const fiber = nextEffect;
    const firstChild = fiber.child;
    if (
      enableSuspenseLayoutEffectSemantics &&
      fiber.tag === OffscreenComponent &&
      isModernRoot
    ) {
       
      const isHidden = fiber.memoizedState !== null;
      const newOffscreenSubtreeIsHidden = isHidden || offscreenSubtreeIsHidden;
      if (newOffscreenSubtreeIsHidden) {
         
        commitLayoutMountEffects_complete(subtreeRoot, root, committedLanes);
        continue;
      } else {
        if ((fiber.subtreeFlags & LayoutMask) !== NoFlags) {
          const current = fiber.alternate;
          const wasHidden = current !== null && current.memoizedState !== null;
          const newOffscreenSubtreeWasHidden =
            wasHidden || offscreenSubtreeWasHidden;
          const prevOffscreenSubtreeIsHidden = offscreenSubtreeIsHidden;
          const prevOffscreenSubtreeWasHidden = offscreenSubtreeWasHidden;