Added rough support for dejagnu testing. Changes need to be made to autoconf to provi...

Added rough support for dejagnu testing. Changes need to be made to autoconf to provide the target_triplet and to check for 'grep -C' which would be used instead of the python script we have now. Eventually the python script should be converted to bash.
The dejagnu-clean needs to be fixed to use find.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17555 91177308-0d34-0410-b5e6-96231b3b80d8