[utils] Remove C++Tests that I don't think anyone uses anymore.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173490 91177308-0d34-0410-b5e6-96231b3b80d8
[utils] Remove the OptionalTests subdir no one runs.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173491 91177308-0d34-0410-b5e6-96231b3b80d8