[clang] [CIR][AArch64] Upstream widening-addition and vector-shift-left-and-widen NEON builtins (PR #204285)

[Vicky Nguyen via cfe-commits]

iamvickynguyen wrote:

Hi @banach-space and @E00N777 , I've rebased and port vshll tests to neon/intrinsics.c. This PR is ready to be reviewed. Thank you!

https://github.com/llvm/llvm-project/pull/204285