[PM] Port DeadArgumentElimination to the new PM

The approach taken here follows r267631.

deadarghaX0r should be easy to port when the time comes to add new-PM
support to bugpoint.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272507 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed