STYLE: Fix lint error "F811 redefinition of unused 'setup'" in benchmarks 
(related to #22884)

There is an issue in the linting of the benchmarks, caused by how `asv` manages reusing a `setup` function. See:
```
(pandas-dev) [mgarcia@xps asv_bench]$ flake8 --config=none benchmarks/categoricals.py 
benchmarks/categoricals.py:21:5: F811 redefinition of unused 'setup' from line 14
```

The problem is that to make `asv` reuse a common `setup` function for all the benchmarks in a file, it is expected to have it defined in the top-level namespace. Then every benchmark class in the file can specify a `setup` method that will be executed after the common one. See this sample code:
```python
from .pandas_vb_common import setup

class MyBenchmark:
    def setup(self):
        pass
```

Regardless if this is a good approach by `asv`, the problem is that the previous code causes linting problems (the error shown before). In this case, the `setup` defined in `pandas_vb_common.py` simply defines the seed, `np.random.seed(1234)`.

It's not a great option, but we could move the import of `setup` at the end of the file (so, the methods are not seen as redefinitions), and flag it to ignore the validation of not being used: `from .pandas_vb_common import setup  # noqa: F401`. But I find this one trickier, as it's difficult to see that there is a common setup being executed, unless you go at the end of the file.

Those are the affected files:
```
benchmarks/ctors.py
benchmarks/series_methods.py
benchmarks/panel_methods.py
benchmarks/inference.py
benchmarks/replace.py
benchmarks/groupby.py
benchmarks/algorithms.py
benchmarks/timeseries.py
benchmarks/binary_ops.py
benchmarks/stat_ops.py
benchmarks/index_object.py
benchmarks/frame_methods.py
benchmarks/panel_ctor.py
benchmarks/eval.py
benchmarks/reshape.py
benchmarks/categoricals.py
benchmarks/rolling.py
benchmarks/gil.py
benchmarks/indexing.py
benchmarks/multiindex_object.py
benchmarks/sparse.py
benchmarks/frame_ctor.py
benchmarks/plotting.py
benchmarks/join_merge.py
benchmarks/attrs_caching.py
benchmarks/reindex.py
benchmarks/io/stata.py
benchmarks/io/csv.py
benchmarks/io/sql.py
benchmarks/io/json.py
benchmarks/io/msgpack.py
benchmarks/io/hdf.py
benchmarks/io/excel.py
benchmarks/io/pickle.py
```