Consolidate bitwise operation implementations

[alamb]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
I spent quite a while reading the code for various bitwise kernels while working
with @rluvaton on

• feat: add apply_unary_op and apply_binary_op bitwise operations #8619

I found there are many different, somewhat overlapping functions that are spread over the codebase

This makes it

1. Hard to find the appropriate API
2. Harder to optimize the correct operations as it is not clear always where
   the relevant code is is located

I also think my experience in #8793 suggests there is significant room for optimization,
and that it is important to have two sets of functions: Modify in place and return new buffer

I think part of the current state is somewhat due to history and some of these functions predated the Buffer APIs

Describe the solution you'd like
I would like the implementation for the "core" APIs to be clear:

1. Create a new Buffer from a unary / binary bitwise operation
2. Apply a unary/binary bitwise operation to an existing Mutable buffer in place

After #8619 we have 2

Describe alternatives you've considered

Thus, I propose we do the following:

1. Add new Buffer::bitwise_unary and Buffer::bitwise_binary functions (that do the same thing as bitwise_bin_op_helper and bitwise_unary_op_helper) but are easier to find and use, and consistently named with PrimitiveArray::unary and PrimitiveArray::binary functions: Add Buffer::from_bitwise_unary and Buffer::from_bitwise_binary me… #8854
2. Add BooleanArray::binary and BooleanArray::unary functions that use the new Buffer functions internally
3. Deprecate bitwise_bin_op_helper, and bitwise_unary_op_helper in favor of the new Buffer methods
4. Deprecate special methods such as buffer_bin_or methods in favor of using the new Buffer methods directly
5. Consolidate bitwise kernel benchmarks

Then we'll basically have two core APIs:

1. Apply bitwise operations in place (via apply_bitwise_unary / apply_bitwise_binary introduced in feat: add apply_unary_op and apply_binary_op bitwise operations #8619)
2. Create a new buffer with the result of bitwise operations (via Buffer::bitwise_unary / Buffer::bitwise_binary)

Then all other APIs will then be thin wrappers around the core APIs and we can spend optimziation and testing efforts on these two core APIs.

Additional context

[alamb]

FYI @Dandandan and @jhorstmann who I think love some good bit h4x0ring

[joe-ucp]

@alamb just submitted a PR for this issue. Any feedback is greatly appreciated! This one was tricky. 😅

[joe-ucp]

I have opened two focused PRs that address the core bitwise and bitmap improvements:

• #8876 – Adds BooleanArray::binary and BooleanArray::unary, both backed by the new buffer-level bitwise APIs.
• #8877 – Refactors nullif to leverage these same buffer-level APIs, and documents the bitmap layout contract (covering validity bitmaps and offset handling).

Both PRs are intentionally scoped to the bitmap/bitwise functionality. They do not include deprecation or call-site cleanups, nor do they address benchmark consolidation at this stage—making them easier to review in isolation.

I'm happy to iterate based on feedback for these two PRs. If these changes are merged, I'm also interested in contributing to follow-up benchmarking work.