[PM] Add names to passes under the new pass manager, and a debug output

[PM] Add names to passes under the new pass manager, and a debug output
mode that can be used to debug the execution of everything.

No support for analyses here, that will come later. This already helps
show parts of the opt commandline integration that isn't working. Tests
of that will start using it as the bugs are fixed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199004 91177308-0d34-0410-b5e6-96231b3b80d8