[clang] [clang][CodeGen] Fix metadata when vectorization is disabled by pragma (PR #135163)

[Luke Lau via cfe-commits]

https://github.com/lukel97 approved this pull request.

Thanks, LGTM. Though this is a part of the code that I'm not familiar with so probably best to wait for another LGTM

https://github.com/llvm/llvm-project/pull/135163