Chore: refactor bit_count

[kazantsev-maksim]

Which issue does this PR close?

Part of: #2443

Rationale for this change

Part of: #2443

What changes are included in this PR?

How are these changes tested?

Tested with existing unit tests

[kazantsev-maksim]

The DataFusion implementation produces results that are not compatible with Spark

Project [bit_count(col2#2190) AS bit_count(col2)#2218]
+- Relation spark_catalog.default.bitwise_count_test[col1#2189L,col2#2190,col3#2191,col4#2192] parquet

== Physical Plan ==
*(1) CometColumnarToRow
+- CometProject [bit_count(col2)#2218], [bit_count(col2#2190) AS bit_count(col2)#2218]
+- CometScan [native_iceberg_compat] parquet spark_catalog.default.bitwise_count_test[col2#2190] Batched: true, DataFilters: [], Format: CometParquet, Location: InMemoryFileIndex(1 paths)[file:/Users/tendoo/Desktop/datafusion-comet/spark/spark-warehouse/bitw..., PartitionFilters: [], PushedFilters: [], ReadSchema: structcol2:int

== Results ==

== Results ==
!== Correct Answer - 3 == == Spark Answer - 3 ==
struct<bit_count(col2):int> struct<bit_count(col2):int>
![31] [1]
![33] [31]
[6] [6] (QueryTest.scala:244)

@andygrove @comphead

[comphead]

Triggering CI