[PM] Push the debug option for the new pass manager into the opt tool

[PM] Push the debug option for the new pass manager into the opt tool
and expose the necessary hooks in the API directly.

This makes it much cleaner for example to log the usage of a pass
manager from a library. It also makes it more obvious that this
functionality isn't "optional" or "asserts-only" for the pass manager.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225841 91177308-0d34-0410-b5e6-96231b3b80d8