Refactor histogram reduction using cuco::static_set::insert_and_find

[srinivasyadav18]

Description

Refactors histogram reduce and groupby aggregations using cuco::static_set::insert_and_find. Speed improvement results here and here.

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[mhaseeb123]

No longer in use

[PointKernel]

LGTM

Requesting @ttnghia's review as he worked on the original hash reduce-by-row implementation.

[ttnghia]

This is error prone. Suppose that now we want to support the nested types, it will be difficult to trace back to this line of code to change it. So I would rather implement the code path ready for nested types here, like what it was before:

if (has_nested_columns) {
    auto const key_equal = row_comp.equal_to<true>(has_nulls, null_equality::EQUAL, value_comp);
    map.insert(pair_iter, pair_iter + input.num_rows(), key_hasher, key_equal, stream.value());
  } else {
    auto const key_equal = row_comp.equal_to<false>(has_nulls, null_equality::EQUAL, value_comp);
    map.insert(pair_iter, pair_iter + input.num_rows(), key_hasher, key_equal, stream.value());
  }

[PointKernel]

Good point about the implicit use of non-nested key equality. Instead of adding a code path for nested types that isn't used by any existing code, I suggest leaving the code as is and adding a CUDF_EXPECTS check to ensure no nested types are involved in the calculation. This approach also avoids templating functions, which can help reduce build time.

[ttnghia]

The performance improvement is fantastic. There's just one small request.

[mhaseeb123]

The performance improvement is fantastic. There's just one small request.

Reverting the added functor which enabled the unused code path in light of Yunsong's comment.

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[mhaseeb123]

/merge