[llvm] [LV][NFC] Autogen a test with integer costs per lane (PR #201560)

[David Sherwood via llvm-commits]

david-arm wrote:

If people prefer I am happy to split up this PR into smallers to add the new flags first (if people think they're useful). I just wanted them to all be in the same PR initially so it's easy to see the motivation for them.

https://github.com/llvm/llvm-project/pull/201560