clang-format the dead code elimination pass

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@171843 91177308-0d34-0410-b5e6-96231b3b80d8
Dead code elimination: Make variable names uppercase

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@171844 91177308-0d34-0410-b5e6-96231b3b80d8