arrow

GH-37333: [Python] Replace pandas.util.testing.rands with vendored version (#42089)

### Rationale for this change

Fixes https://github.com/apache/arrow/issues/37333.

### What changes are included in this PR?

- Replaces the calls to `pandas.util.testing.rands` with existing `pyarrow.tests.util.rands`
- Updated benchmarks.rst to remove a mention of the now-deprecated `asv dev` command.

### Are these changes tested?

I tested locally in a freshly-created python venv and a conda environment and the benchmarks run without error.

### Are there any user-facing changes?

No.
* GitHub Issue: #37333

Authored-by: Bryce Mecum <petridish@gmail.com>
Signed-off-by: Joris Van den Bossche <jorisvandenbossche@gmail.com>