TST: dataframe constructor should preserve order with standard Python dicts
We have a couple of dataframe tests (xref #13304) related to column ordering when constructed from an `OrderedDict`:
https://github.com/pandas-dev/pandas/blob/e4cf3abe0020aa801950e0383fffc13ee9703456/pandas/tests/frame/test_constructors.py#L1250-L1288

As of [PEP 468](https://www.python.org/dev/peps/pep-0468/) standard dictionaries are ordered so these tests should also work with `OrderedDict` replaced by `dict`