[clang] [Clang][X86] Replace unnecessary `vfmadd*` builtins with `element_wise_fma` (PR #152545)

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moorabbit wrote:

The clang-format changes [b1f12e0](https://github.com/llvm/llvm-project/pull/152545/commits/b1f12e09ef09b347dbdfffe05f030b52b491f890) seem very large. Should I try and undo them?

Also, let me know if I should break this ([f6ac261](https://github.com/llvm/llvm-project/pull/152545/commits/f6ac261dd7bccbe1085b453fec2fd73f310ad09e)) into smaller PRs.

https://github.com/llvm/llvm-project/pull/152545