[llvm] [InstCombine] Remove the canonicalization of `trunc` to `i1` (PR #84628)

[via llvm-commits]

goldsteinn wrote:

This isn't a bad thought, but think the comment still applies, looking through the test changes there are some regressions that indicate we handle `trunc i1` in all the cases we should.

I am supportive of this effort, but can you please also make patches to cleanup the regressions?

https://github.com/llvm/llvm-project/pull/84628