Auto merge of #120370 - x17jiri:likely_unlikely_fix, r=saethlin

Likely unlikely fix

RFC 1131 ( https://github.com/rust-lang/rust/issues/26179 ) added likely/unlikely intrinsics, but they have been broken for a while: https://github.com/rust-lang/rust/issues/96276 , https://github.com/rust-lang/rust/issues/96275 , https://github.com/rust-lang/rust/issues/88767 . This PR tries to fix them.

Changes:
- added a new `cold_path()` intrinsic
- `likely()` and `unlikely()` changed to regular functions implemented using `cold_path()`

compiler/rustc_hir_analysis/src/check/intrinsic.rs

@@ -109,9 +109,8 @@ pub fn intrinsic_operation_unsafety(tcx: TyCtxt<'_>, intrinsic_id: LocalDefId) -
         | sym::three_way_compare
         | sym::discriminant_value
         | sym::type_id
-        | sym::likely
-        | sym::unlikely
         | sym::select_unpredictable
+        | sym::cold_path
         | sym::ptr_guaranteed_cmp
         | sym::minnumf16
         | sym::minnumf32
@@ -489,9 +488,8 @@ pub fn check_intrinsic_type(
             sym::float_to_int_unchecked => (2, 0, vec![param(0)], param(1)),
 
             sym::assume => (0, 0, vec![tcx.types.bool], tcx.types.unit),
-            sym::likely => (0, 0, vec![tcx.types.bool], tcx.types.bool),
-            sym::unlikely => (0, 0, vec![tcx.types.bool], tcx.types.bool),
             sym::select_unpredictable => (1, 0, vec![tcx.types.bool, param(0), param(0)], param(0)),
+            sym::cold_path => (0, 0, vec![], tcx.types.unit),
 
             sym::read_via_copy => (1, 0, vec![Ty::new_imm_ptr(tcx, param(0))], param(0)),
             sym::write_via_move => {