[llvm] [Vectorize] Remove unused functions (NFC) (PR #226392)

[Luke Lau via llvm-commits]

https://github.com/lukel97 requested changes to this pull request.

Sorry for the request changes, can move the VPlanPatternMatch changes to another PR? Some of those might be used by future PRs

https://github.com/llvm/llvm-project/pull/226392