Fix #337

[tomaka]

Fix #337
Amends #335

While less efficient this alternative implementation is for sure correct.

[github-actions]

twiggy diff report

Difference in .wasm size before and after this pull request.

---

 Delta Bytes │ Item
─────────────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
        +604 ┊ <alloc::collections::btree::map::BTreeMap<K,V,A> as core::clone::Clone>::clone::clone_subtree::h953e9994aa36d328
        +602 ┊ smoldot::trie::calculate_root::AllKeys::inject::h10a464b5d8ba0f83
        -602 ┊ smoldot::trie::calculate_root::AllKeys::inject::h1c293bfdc8a6798d
        -457 ┊ <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold::hdf71814a25fd23f8
        +457 ┊ <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold::hf6a9c3e3aa62d785
        +324 ┊ hashbrown::raw::RawTable<T,A>::clone_from_impl::h11d3b16c1f565d48
        -323 ┊ smoldot::executor::storage_diff::TrieDiff<T>::merge_map::ha824ec590d17814a
        +284 ┊ alloc::collections::btree::navigate::<impl alloc::collections::btree::node::NodeRef<BorrowType,K,V,alloc::collections::btree::node::marker::LeafOrInternal>>::find_leaf_edges_spanning_range::h4e63ab17377a80c0
        +236 ┊ alloc::collections::btree::navigate::<impl alloc::collections::btree::node::Handle<alloc::collections::btree::node::NodeRef<BorrowType,K,V,alloc::collections::btree::node::marker::LeafOrInternal>,alloc::collections::btree::node::marker::KV>>::next_leaf_edge::h80edcfb3808023c0
        +183 ┊ <hashbrown::raw::RawTable<T,A> as core::clone::Clone>::clone::h89275c5a4c6205cb
        +144 ┊ data[0]
        +128 ┊ alloc::collections::btree::node::Handle<alloc::collections::btree::node::NodeRef<BorrowType,K,V,alloc::collections::btree::node::marker::LeafOrInternal>,Type>::force::h67581f89c0170655
        +126 ┊ hashbrown::raw::RawTable<T,A>::new_uninitialized::h90397915df4d35e0
        -114 ┊ <hashbrown::map::HashMap<K,V,S,A> as core::iter::traits::collect::Extend<(K,V)>>::extend::ha6c743f4f39650ef
        +114 ┊ <hashbrown::map::HashMap<K,V,S,A> as core::iter::traits::collect::Extend<(K,V)>>::extend::hcc0a6abad3ca51b3
        -109 ┊ <hashbrown::set::HashSet<T,S,A> as core::iter::traits::collect::FromIterator<T>>::from_iter::h4533947ca5c21681
        +109 ┊ <hashbrown::set::HashSet<T,S,A> as core::iter::traits::collect::FromIterator<T>>::from_iter::h5c30c244f4c8eeb8
         +95 ┊ <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold::h983da7035cf260a9
         -95 ┊ <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold::ha2208f36d41fb174
         -95 ┊ <hashbrown::set::HashSet<T,S,A> as core::iter::traits::collect::Extend<T>>::extend::h211b2049d988d4e9
        +418 ┊ ... and 17 more.
       +3384 ┊ Σ [37 Total Rows]