Return value of coroutine_layout fn changed to Result with LayoutError
Continue of https://github.com/rust-lang/rust/pull/140902:
`coroutine_layout` fn is now returns `Result` with `LayoutError` to have consistent error with `layout_of_uncached`.
`async_drop_coroutine_layout` fn is now return `LayoutError::TooGeneric` in case of not-fully-specialized `async_drop_in_place<T>::{closure}` coroutine.