[llvm] [mlir] [MLIR] Add debug log to the pass manager (NFC) (PR #156205)

[Mehdi Amini via llvm-commits]

joker-eph wrote:

> On a related note, with https://github.com/llvm/llvm-project/pull/156205 we are effectively creating "stacked PRs". So, IIUC, this [commit](https://github.com/llvm/llvm-project/pull/156205/commits/7606fa3d0b689abbfbd6446dc9f1019e38567106) no longer belongs to this PR. Could you either update the summary or use one of the other methods that we use for stacked PRs?

The problem with stacked PR is that you need to know that you'll do a stack before pushing, because the branch needs to be in the llvm repo. When I opened this, I unfortunately did from my fork and not from a user branch in the llvm repo, which means that to make this PR part of a stack I have to close it and open a new one from a branch in the repo.
I can do that but we'll lose the review history.

https://github.com/llvm/llvm-project/pull/156205