[llvm] [CostModel] Estimate the codesize cost of switch (PR #163569)

[Hongyu Chen via llvm-commits]

XChy wrote:

> This looks reasonable to me, but why does this impact vectorization tests? Do those use the CodeSize model even when not optimizing for size?

Hmm, I am not familiar with the vectorizer code, just updated these tests according to CI. Maybe @fhahn knows some details?

https://github.com/llvm/llvm-project/pull/163569