Use 128 bits for TypeId hash

- Switch TypeId to 128 bits
- Hack around the fact that tracing-subscriber dislikes how TypeId is hashed
- Remove lowering of type_id128 from rustc_codegen_llvm
- Remove unnecessary `type_id128` intrinsic (just change return type of `type_id`)
- Only hash the lower 64 bits of the TypeId
- Reword comment

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -77,7 +77,7 @@ pub(crate) fn eval_nullary_intrinsic<'tcx>(
         }
         sym::type_id => {
             ensure_monomorphic_enough(tcx, tp_ty)?;
-            ConstValue::from_u64(tcx.type_id_hash(tp_ty).as_u64())
+            ConstValue::from_u128(tcx.type_id_hash(tp_ty).as_u128())
         }
         sym::variant_count => match tp_ty.kind() {
             // Correctly handles non-monomorphic calls, so there is no need for ensure_monomorphic_enough.
@@ -169,7 +169,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let ty = match intrinsic_name {
                     sym::pref_align_of | sym::variant_count => self.tcx.types.usize,
                     sym::needs_drop => self.tcx.types.bool,
-                    sym::type_id => self.tcx.types.u64,
+                    sym::type_id => self.tcx.types.u128,
                     sym::type_name => self.tcx.mk_static_str(),
                     _ => bug!(),
                 };