There are have been a few issues around people using case sensitive file systems
what Xcode/clang does when looking at the paths. In attempts to solve one set of
warnings, new warnings/errors happened in different setup. So, to hopefully put
these problem away for got, move the WKTs to be at the same level as the other
headers.
- Revert "Override CocoaPods module to lowercase (#6464)"
This reverts commit 479ba8226b.
- Move WKTs to the objectivec directory and make the old headers shim back to
the new locations.
- Update objectivec/generate_well_known_types.sh to check them one at a time
and to deal with the new locations for them.
Fixes#6803
