Add several CFG-stress-testing input source files. These use the
preprocessor to build up very large CFGs in various shapes that can
produce different algorithmic behavior in CFG-walking code.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134698 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed