stabilize duration_from_nanos_u128

[RalfJung]

libs-api FCP passed in #139201.
Closes #139201.

@oli-obk would you prefer if we did a const-hack to avoid allowing const_trait_impl here?

[rustbot]

⚠️ #[rustc_allow_const_fn_unstable] needs careful audit to avoid accidentally exposing unstable
implementation details on stable.

cc @rust-lang/wg-const-eval

The Miri subtree was changed

cc @rust-lang/miri

[rustbot]

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