LLVM r236120 renamed debug info IR constructs to use a `DI` prefix, now
that the `DIDescriptor` hierarchy has been gone for about a week. This
commit was generated using the rename-md-di-nodes.sh upgrade script
attached to PR23080, followed by running clang-format-diff.py on the
`lib/` portion of the patch.
llvm-svn: 236121
Mostly, try to depend on the annotation comments more so these tests are more
legible, brief, and agnostic to schema changes in the future (sure, they're not
agnostic to changes to the comment annotations but since they're easier to read
they should be easier to update if that happens).
llvm-svn: 177457