Updated to isl 2c19ecd444095d6f560349018f68993bc0e03691

  Changed test cases and fixed warnings.


git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@218043 91177308-0d34-0410-b5e6-96231b3b80d8
Allow the IslExprBuilder to compare pointers


git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@218044 91177308-0d34-0410-b5e6-96231b3b80d8