[llvm] [loop-interchange] Move tests to use remarks (PR #123053)

[Sjoerd Meijer via llvm-commits]

sjoerdmeijer wrote:

> Given that we don't want assembly output now, can we remove `-S` and also redirection to `&1` from the tests?

Thanks, I will remove `-S` and add `-disable-output` before merging this.

https://github.com/llvm/llvm-project/pull/123053