Invoke PruneEH pass before Sample Profile pass.

Summary: We need to call PruneEH pass before AutoFDO pass so that some EH-related calls can get inlined in Sample Profile pass.

Reviewers: davidxl, dnovillo

Subscribers: junbuml, llvm-commits

Differential Revision: http://reviews.llvm.org/D21197

llvm-svn: 273298