After feedback from D122861, do the same thing with some of the other headers. Try to move the
headers so they have a similar style and way of doing things.
Reviewed By: ldionne, daltenty
Differential Revision: https://reviews.llvm.org/D124227
We do ship those headers, so the directory name should not be something
that can potentially conflict with user-defined directories.
Differential Revision: https://reviews.llvm.org/D95956