Rollup merge of #121629 - RalfJung:field-shuffle-seed, r=oli-obk

fix some references to no-longer-existing ReprOptions.layout_seed

Seems like the field got renamed but some comments not updated.

compiler/rustc_abi/src/layout.rs

@@ -958,7 +958,7 @@ fn univariant<
             #[cfg(feature = "randomize")]
             {
                 use rand::{seq::SliceRandom, SeedableRng};
-                // `ReprOptions.layout_seed` is a deterministic seed we can use to randomize field
+                // `ReprOptions.field_shuffle_seed` is a deterministic seed we can use to randomize field
                 // ordering.
                 let mut rng =
                     rand_xoshiro::Xoshiro128StarStar::seed_from_u64(repr.field_shuffle_seed);

compiler/rustc_abi/src/lib.rs

@@ -41,7 +41,7 @@ bitflags! {
         // Internal only for now. If true, don't reorder fields.
         const IS_LINEAR          = 1 << 3;
         // If true, the type's layout can be randomized using
-        // the seed stored in `ReprOptions.layout_seed`
+        // the seed stored in `ReprOptions.field_shuffle_seed`
         const RANDOMIZE_LAYOUT   = 1 << 4;
         // Any of these flags being set prevent field reordering optimisation.
         const IS_UNOPTIMISABLE   = ReprFlags::IS_C.bits()