[-cxx-abi microsoft] Canonicalize array parameters better

Summary:
More accurately characterize the nature of array parameters. Doing this
removes false back-reference opportunities.  Remove some hacks now that
we characterize these better.

Reviewers: rnk, timurrrr, whunt, cdavis5x

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1626