Make some trivial functions `#[inline(always)]` This is some kind of follow-up of PRs like https://github.com/rust-lang/rust/pull/85218, https://github.com/rust-lang/rust/pull/84061, https://github.com/rust-lang/rust/pull/87150. Functions that do very basic operations are made `#[inline(always)]` to avoid pessimizing them in debug builds when compared to using built-in operations directly.