CLN: Fix FutureWarnings in the benchmarks
I see couple of `FutureWarning` in the benchmarks that can be fixed by simply updating the code to the proposed version.

```
·· /home/runner/work/pandas/pandas/asv_bench/benchmarks/algorithms.py:8: FutureWarning: pandas.util.testing is deprecated. Use the functions in the public API at pandas.testing instead.
     from pandas.util import testing as tm
   /home/runner/work/pandas/pandas/asv_bench/benchmarks/sparse.py:5: FutureWarning: The pandas.SparseArray class is deprecated and will be removed from pandas in a future version. Use pandas.arrays.SparseArray instead.
     from pandas import MultiIndex, Series, SparseArray, date_range
```
See for example: https://github.com/pandas-dev/pandas/pull/30746/checks#step:13:21