[#22550] Remove TestData from series-tests test_operators.py
Part of #22550

Replaced TestData usage in `pandas/tests/series/test_operators.py` with`datetime_series` fixture

- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

restarted travis build LGTM thanks @SaturnFromTitan 