[LTO] Add ability to parse AA pipelines.

This is supposed to be a drop in replacement for what lld
provides via --lto-newpm-aa-pipeline.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281774 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed