[llvm] Use MaxStride instead of CommonStride to calculate MaxVF (PR #98142)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

Thanks for putting up the PR, this was an extension I had in mind when I generalized the logic. Could you also add a negative test case (different strides, but not safe)?

https://github.com/llvm/llvm-project/pull/98142