Use C++11 formatting

clang-formats behaviour has changed for a couple of C++11 formattings. We adapt
Polly to ensure our formatting checks are clean again.

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@202650 91177308-0d34-0410-b5e6-96231b3b80d8
ScopDetect: Make foreachs 'const auto &'

We mostly iterate over read-only values. Following a suggestion by Duncan P.N
Exons Smith, we use the construct 'const auto &' for this.

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@202651 91177308-0d34-0410-b5e6-96231b3b80d8