BUG: df.shift(n, axis=1) with multiple blocks
- [x] closes #35488
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

thanks @MeeseeksDev backport to 1.1.x