bench: add array_compact benchmarks (#25566)

## Which issue does this PR close?

- N/A

## Rationale for this change

Add benchmark coverage for `array_compact`.

## What changes are included in this PR?

Cover sliced arrays, child types, row widths, parent nulls, and periodic
and random child-null distributions through the UDF interface.

## What is the testing strategy for this PR?

Ran benchmarks and examined output.

## Are there any user-facing changes?

No.

Author: neilconway

datafusion/functions-nested/Cargo.toml

@@ -70,6 +70,10 @@ rand = { workspace = true }
 # used to test array_transform
 datafusion-physical-expr = { workspace = true }
 
+[[bench]]
+harness = false
+name = "array_compact"
+
 [[bench]]
 harness = false
 name = "array_concat"