REF/CLN: pandas/io/parsers.py
- [ ] closes #xxxx
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Refactor/cleanup ``pandas/io/parsers.py``
- Extract method _refresh_kwargs_based_on_dialect
- Extract method _validate_skipfooter
- Drop local variable engine_specified
- Clean-up FutureWarning issue
