Remove SCEVAAWrapperPass from createLegacyPMAAResults; NFC

Summary:
createLegacyPMAAResults is only called by CGSCC and Module passes, so
the call to getAnalysisIfAvailable<SCEVAAWrapperPass>() never
succeeds (SCEVAAWrapperPass is a function pass).

Reviewers: chandlerc

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D17009

llvm-svn: 260182