Current pass manager, not the parent pass manager, assumes the role of

Current pass manager, not the parent pass manager,  assumes the role of
last user when one of the managed pass uses info provided by parent pass
manager.

This was exposed by LPPassManager work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34936 91177308-0d34-0410-b5e6-96231b3b80d8