[llvm] [LoopVectorize][NFC] Rewrite tests to check output of vplan cost model (PR #113697)

[David Sherwood via llvm-commits]

david-arm wrote:

Hmm, it would be a shame to lose the more useful debug output. Perhaps I'll just rewrite the test to only check for the "3." bit.

https://github.com/llvm/llvm-project/pull/113697