[llvm] [GlobalOpt] Revert global widening transform (PR #144652)

[Nikita Popov via llvm-commits]

nikic wrote:

> Does any of the removed tests show a correctness issue? If so, would be good to keep them or otherwise add a new test?

I could do that, but I think it would be easier to review a reland if it contained all the tests (otherwise it's non-obvious that all negative tests are present).

https://github.com/llvm/llvm-project/pull/144652