CTFE: support assert_zero_valid and assert_uninit_valid This ensures the implementation of all three type-based assert_ intrinsics remains consistent in Miri. `assert_inhabited` recently got stabilized in https://github.com/rust-lang/rust/pull/90896 (meaning stable `const fn` can call it), so do the same with these other intrinsics. Cc ```@rust-lang/wg-const-eval```