This was shipped internally. Cleaning up the flag.

This is a fix for a problem where React retains shadow nodes longer than
it needs to. The behaviour is shown in React Native test:
https://github.com/facebook/react-native/blob/main/packages/react-native/src/private/__tests__/utilities/__tests__/ShadowNodeReferenceCounter-itest.js#L169

When React commits a new shadow tree, old shadow nodes are stored inside
`fiber.alternate.stateNode`. This is not cleared up until React clones
the node again. This may be problematic if mutation deletes a subtree,
in that case `fiber.alternate.stateNode` will retain entire subtree
until next update. In case of image nodes, this means retaining entire
images.

So when React goes from revision A: `<View><View /></View>` to revision
B: `<View />`, `fiber.alternate.stateNode` will be pointing to Shadow
Node that represents revision A..

![image](https://github.com/user-attachments/assets/076b677e-d152-4763-8c9d-4f923212b424)

To fix this, this PR adds a new feature flag
`enableEagerAlternateStateNodeCleanup`. When enabled,
`alternate.stateNode` is proactively pointed towards finishedWork's
stateNode, releasing resources sooner.

I have verified this fixes the issue [demonstrated by React Native
tests](https://github.com/facebook/react-native/blob/main/packages/react-native/src/private/__tests__/utilities/__tests__/ShadowNodeReferenceCounter-itest.js#L169).
All existing React tests pass when the flag is enabled.

Enables the `enableEagerAlternateStateNodeCleanup` feature flag for all
variants, while maintaining the `__VARIANT__` for the internal React
Native flavor for backtesting reasons.

```
$ yarn test
```

…ackTrace (#33143)

When we get the source location for "View source for this element" we
should be using the enclosing function of the callsite of the child. So
that we don't just point to some random line within the component.

This is similar to the technique in #33136.

This technique is now really better than the fake throw technique, when
available. So I now favor the owner technique. The only problem it's
only available in DEV and only if it has a child that's owned (and not
filtered).

We could implement this same technique for the error that's thrown in
the fake throwing solution. However, we really shouldn't need that at
all because for client components we should be able to call
`inspect(fn)` at least in Chrome which is even better.

`react-stack-bottom-frame` -> `react_stack_bottom_frame`.

This survives `@babel/plugin-transform-function-name`, but now frames
will be displayed as `at Object.react_stack_bottom_frame (...)` in V8.
Checks that were relying on exact function name match were updated to
use either `.indexOf()` or `.includes()`

For backwards compatibility, both React DevTools and Flight Client will
look for both options. I am not so sure about the latter and if React
version is locked.

Updates the version numbers in the prerelease channels.

https://www.npmjs.com/package/eslint-plugin-react-hooks/v/6.0.0 was just
released, so we can bump this now.

…s version (#33972)