Remove 'dry run' functionality throughout.
Summary of changes
At first, I considered deprecating this functionality. Then I realized that this functionality is exposed almost exclusively through a parameter to setup.py, which is already deprecated. Moreover, it seems unlikely that anyone would use this functionality in today's modern usage. I personally haven't used it even going back to the most legacy usage.
Removing these changes from Setuptools should unblock the failing tests in pypa/distutils#335, and in fact, maybe they should be merged together for easier rollback if needed. [Update] The changes from pypa/distutils#335 are included in this merge.
Ref pypa/distutils#334
Pull Request Checklist
- [x] Changes have tests
- [x] News fragment added in
newsfragments/. (See documentation for details)
@abravalheri Any reservations before I proceed with merging?