Avoid redundant memory access in ArrowBytesViewMap for inline values

[CuteChuanChuan]

Which issue does this PR close?

• Closes Avoid extra memory access in ArrowByteViewMap #20054 .

Rationale for this change

ArrowBytesViewMap::insert_if_new_inner calls values.value(i) redundantly:

1. Inside the find closure
2. Again during insertion when the value is new

For inline strings (<=12 bytes), values.value(i) is unnecessary since the data is embedded directly in the view.
For non-inline strings (>12 bytes), it should only be called once.

What changes are included in this PR?

• Inline strings (<=12 bytes): Extract bytes directly instead of calling values.value(i). During insertion, push the original view_u128 directly.
• Non-inline strings (>12 bytes): Fetch values.value(i) once before the find closure and reuse the result for both hash resolution and insertion.

Are these changes tested?

Yes, covered by existing tests by running cargo test -p datafusion-physical-expr-common

Are there any user-facing changes?

No. This is an internal performance optimization with no API changes.

[CuteChuanChuan]

Hi @Dandandan ,
could you PTAL when you have chances? Thanks! 🙏

[Dandandan]

I think we don'nt need this for the inline path (we use the u128 directly)

[Dandandan]

Hmm can we just values.value(i).as_ref() to where it is used instead in the else branch ?

[Dandandan]

it looks like this param to the payload fn is not really used anymore, could we remove it?

The three actual implementations just ignore the param:

        fn make_payload_fn(_value: Option<&[u8]>) {}

            |_value| {
                // assign new group index on each insert
                let group_idx = self.num_groups;
                self.num_groups += 1;
                group_idx
            },

            |_value| {
                // assign new group index on each insert
                let group_idx = self.num_groups;
                self.num_groups += 1;
                group_idx
            },