Rollup merge of #121695 - oli-obk:split_ty_utils, r=compiler-errors

Split rustc_type_ir to avoid rustc_ast from depending on it

unblocks #121576

and resolves a FIXME in `rustc_ast`'s `Cargo.toml`

The new crate is tiny, but it will get bigger in #121576

compiler/rustc_middle/src/mir/interpret/error.rs

@@ -4,6 +4,7 @@ use crate::error;
 use crate::mir::{ConstAlloc, ConstValue};
 use crate::ty::{layout, tls, Ty, TyCtxt, ValTree};
 
+use rustc_ast_ir::Mutability;
 use rustc_data_structures::sync::Lock;
 use rustc_errors::{
     DiagnosticArgName, DiagnosticArgValue, DiagnosticMessage, ErrorGuaranteed, IntoDiagnosticArg,
@@ -12,7 +13,6 @@ use rustc_macros::HashStable;
 use rustc_session::CtfeBacktrace;
 use rustc_span::{def_id::DefId, Span, DUMMY_SP};
 use rustc_target::abi::{call, Align, Size, VariantIdx, WrappingRange};
-use rustc_type_ir::Mutability;
 
 use std::borrow::Cow;
 use std::{any::Any, backtrace::Backtrace, fmt};

compiler/rustc_middle/src/ty/mod.rs

@@ -32,6 +32,7 @@ pub use generic_args::*;
 pub use generics::*;
 use rustc_ast as ast;
 use rustc_ast::node_id::NodeMap;
+pub use rustc_ast_ir::{Movability, Mutability};
 use rustc_attr as attr;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_data_structures::intern::Interned;