Use rint instead of roundeven

Use rint intrinsic instead of roundeven to impement `round_ties_even`. They do the same thing when rounding mode is default, which Rust assumes.
And `rint` has better platform support.

Keeps `roundeven` around in `core::intrinsics`, it's doing no harm there.

library/std/src/f64.rs

@@ -119,7 +119,7 @@ impl f64 {
     #[unstable(feature = "round_ties_even", issue = "96710")]
     #[inline]
     pub fn round_ties_even(self) -> f64 {
-        unsafe { intrinsics::roundevenf64(self) }
+        unsafe { intrinsics::rintf64(self) }
     }
 
     /// Returns the integer part of `self`.