[GSoC] Add PolyhedralInfo pass - new interface to polly analysis

  Adding a new pass PolyhedralInfo. This pass will be the interface to Polly.
  Initially, we will provide the following interface:
    - #IsParallel(Loop *L) - return a bool depending on whether the loop is
                             parallel or not for the given program order.

Patch by Utpal Bora <cs14mtech11017@iith.ac.in>

Differential Revision: https://reviews.llvm.org/D21486

llvm-svn: 276637