[Polly][NewPM] Port ScopDetection to the new PassManager

Summary: This is a proof of concept of how to port polly-passes to the new PassManager architecture.  This approach works ootb for Function-Passes, but might not be directly applicable to Scop/Region-Passes. While we could just run the Analyses/Transforms over functions instead, we'd surrender the nice pipelining behaviour we have now.

Reviewers: Meinersbur, grosser

Reviewed By: grosser

Subscribers: pollydev, sanjoy, nemanjai, llvm-commits

Tags: #polly

Differential Revision: https://reviews.llvm.org/D31459

llvm-svn: 302902