[llvm] [InstCombine] Support trunc to i1 in foldSelectICmpAnd (PR #127905)

[Andreas Jonson via llvm-commits]

andjo403 wrote:

when rebasing I get a merge conflict with the change from https://github.com/llvm/llvm-project/pull/128741 as the second commit that deduplication the code move the code from that commit, it looks like it is possible to use the knownbits for foldSelectICmpAndBinOp also so possible to move to the new foldSelectBitTest function. 

what it the preferred way to merge this PR?

- add some test for the use of known bits in foldSelectICmpAndBinOp to this PR and make the deduplicate commit not NFC
- drop the deduplicate commit from this PR and make a separat PR for that
- make a separat PR that use the known bits in foldSelectICmpAndBinOp and then rebase this PR when the other PR is merged

https://github.com/llvm/llvm-project/pull/127905