[llvm] [IR] Add nowrap flags for trunc instruction (PR #85592)

[via llvm-commits]

elhewaty wrote:

> @elhewaty I've started playing with some vector test coverage already - once this has landed I'll commit the tests, raise a ticket and assign it to you.

Thanks, I am looking forward to it.

https://github.com/llvm/llvm-project/pull/85592