[clang] [libc] [Clang] Rename GPU intrinsic functions from `__gpu_` to `_gpu_` (PR #118674)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

I'm fine with this solution, but I'll sit on it for a bit to see if @AaronBallman has an opinion or if the `clangd` people get back to me on https://github.com/llvm/llvm-project/issues/118684.

https://github.com/llvm/llvm-project/pull/118674