noir-r1cs/src/utils/mod: Cleanup when <https://github.com/rust-lang/rust/issues/96097> lands

[recmo]

On 2025-05-21 @recmo wrote in 3e2e388 “Add PAT”:

Cleanup when rust-lang/rust#96097 lands
Required for MaybeUninit

    const CACHE_SIZE: usize = 1 << 15;
    CACHE_SIZE / size_of::<T>()
}

/// Unzip a [[(T,T); N]; M] into ([[T; N]; M],[[T; N]; M]) using move semantics
// TODO: Cleanup when <https://github.com/rust-lang/rust/issues/96097> lands
#[allow(unsafe_code)] // Required for `MaybeUninit`
fn unzip_double_array<T: Sized, const N: usize, const M: usize>(
    input: [[(T, T); N]; M],
) -> ([[T; N]; M], [[T; N]; M]) {
    // Create uninitialized memory for the output arrays
    let mut left: [[MaybeUninit<T>; N]; M] = [const { [const { MaybeUninit::uninit() }; N] }; M];

From noir-r1cs/src/utils/mod.rs:35