dillon1000/react

[Fiber] Don't unhide a node if a direct parent offscreen is still hidden (#34821)

If an inner Offscreen commits an unhide, but an outer Offscreen is still
hidden but they're controlling the same DOM node then we shouldn't
unhide the DOM node yet.

This keeps track of whether we're directly inside a hidden offscreen. It
might be better to just do the tree search instead of keeping the stack
state since it's a rare case. Although this hide/unhide path does
trigger a lot of times even when there's no change.

This was technically a bug with Suspense too but it doesn't appear
because a suspended Suspense boundary never commits its partial state.
If it did, it would trigger this same path. But it can happen with an
outer Activity and inner Suspense.