Added file paths to ignore in linter scripts/validate_unwanted_patterns.py
- [ ] closes #xxxx
- [ ] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

---

While running ```./ci/code_checks.sh lint``` on my local machine I got the output of:

```
Check for use of not concatenated strings
./asv_bench/env/40d026129f63c107b1ac48bf9ad6964c/lib/python3.6/_sitebuiltins.py:99:String unnecessarily split in two by black. Please merge them manually..
./asv_bench/env/40d026129f63c107b1ac48bf9ad6964c/lib/python3.6/inspect.py:2768:String unnecessarily split in two by black. Please merge them manually..
./asv_bench/env/40d026129f63c107b1ac48bf9ad6964c/lib/python3.6/inspect.py:2890:String unnecessarily split in two by black. Please merge them manually..

....
```

This fixes it.