[llvm] [Clang][Codegen] fix vector data by modifying VMVN (PR #105913)

[David Green via llvm-commits]

davemgreen wrote:

I think I would fold this into #105519. If this is not affecting any tests then the might not be any big endian test coverage for them at the moment. I've added a few extra tests in 9f82f6daa5e470652f4ffced628547d0c24aac2c

https://github.com/llvm/llvm-project/pull/105913