[C++] Add benchmarks for arrow/util/rle_encoder.h for non-dictionary encodings.

[asfimport]

#7143 is going to add benchmarks to arrow-reader-writer-benchmarks, but these only cover dictionary encoded cases.  It is hard to force non-dictionary encoding so we should try to write some benchmarks that give a better sense of how that path changes with any algorithm changes.

 

It isn't clear how much this code path is exercised in practice so I'm not sure on the priority.

Reporter: Micah Kornfield / @emkornfield

_{Note: This issue was originally created as ARROW-8760. Please see the migration documentation for further details.}

[thisisnic]

This issue hasn't had activity in a long time. If it's still being worked on, please leave a comment. Otherwise, it will be closed on 23rd June.

Labelled Status: Stale-Warning for tracking.