arrow

GH-41035: [C++] Add a grouper benchmark for preventing performance regression (#41036)



### Rationale for this change
Add a grouper benchmark for preventing performance regression . 

https://github.com/apache/arrow/pull/40998#issuecomment-2039204161.

### What changes are included in this PR?
Added a benchmark.

### Are these changes tested?
Needn't.

### Are there any user-facing changes?
No

* GitHub Issue: #41035

Authored-by: ZhangHuiGui <hugo.zhang@openpie.com>
Signed-off-by: Antoine Pitrou <antoine@python.org>