Update CLooG and some test cases

This is necessary to avoid test failures in the CLooG test suite due to the
recent isl update.

We also need to update two polly test cases which rely on a certain order in the
textual description that isl chooses for its sets and maps. Changes here are not
often, but we should probably switch to a check that verifies such maps are
semantically equivalent instead of represented identically.

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@203476 91177308-0d34-0410-b5e6-96231b3b80d8