Allow to annotate alias scopes in the new SCoP.

  The command line flag -polly-annotate-alias-scopes controls whether or not
  Polly annotates alias scopes in the new SCoP (default ON). This can improve
  later optimizations as the new SCoP is basically an alias free environment for
  them.



git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@218877 91177308-0d34-0410-b5e6-96231b3b80d8