[inductor] use native fetch_add function for trivial types (#101931)
floating-point is supported by std::atomic::fetch_add since C++20.
However, this code path is not activated yet because cpp_flags in codecache.py is hard-coded to "-std=c++17"
Pull Request resolved: https://github.com/pytorch/pytorch/pull/101931
Approved by: https://github.com/jgong5, https://github.com/EikanWang, https://github.com/jansel
