[llvm] [DAGCombiner] Inverse transform `(select c, (and X, 1), 0)` -> `(and (zext c), X)` (PR #66793)

[Nikita Popov via llvm-commits]

nikic wrote:

@goldsteinn If you manually push a change, you need to do something like this
```
git checkout foo
git fetch upstream
git rebase upstream/main

git push -f fork foo
git push upstream foo:main
```
to keep the association between the PR and the commits (the salient part being the last two lines).

If you don't do that, please edit the commit messages to include something like "Closes #xyz" to create a back-link to the PR.

https://github.com/llvm/llvm-project/pull/66793