CLN: Clean csv files in test data GH34427
- [x] closes #34427
- [x] tests passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

I deleted the `iris.csv` and `tips.csv` files which are unused duplicates (i.e. those in `pandas/tests/io/data/csv`). 
