[clang] [Clang] Replace some x86 sqrt builtins with the generic __builtin_elementwise_sqrt versions (PR #165682)

[Simon Pilgrim via cfe-commits]

RKSimon wrote:

@philnik777 Please can you get this committed soon after the CI has passed? We have a lot of churn on BuiltinsX86.td at the moment with the constexpr work so this will bitrot if we're not quick :) 

https://github.com/llvm/llvm-project/pull/165682