Some people have weird CI systems that run each test subdirectory
independently without access to other parallel trees.
Unfortunately, this means we have to suffer some duplication until Art
can sort out how to share these types.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@270164 91177308-0d34-0410-b5e6-96231b3b80d8
Reid Kleckner