[Polly][PM] Register polly passes with the opt tool for the new-pm path

Summary: When polly is linked into the tools because of the LLVM_POLLY_LINK_INTO_TOOLS option being set, we need to register its passes with the PassBuilder. Because polly is linked in, we can directly call its callback registration method, which registers the appropriate callbacks with the new PM's PassBuilder. This essentially follows exactly the way it worked with the legacy PM.

Reviewers: grosser, chandlerc, bollu

Reviewed By: grosser

Subscribers: pollydev, llvm-commits

Differential Revision: https://reviews.llvm.org/D36273

llvm-svn: 310043