[llvm] [LV][NFC] Move and add truncated-related FindLastIV reduction test cases. (PR #67674)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon commented:

Kindly add comments to the newly-added tests, similar to the comments I've written for existing tests.

https://github.com/llvm/llvm-project/pull/67674