Auto merge of #79519 - cjgillot:noattr, r=wesleywiser

Store HIR attributes in a side table

Same idea as #72015 but for attributes.
The objective is to reduce incr-comp invalidations due to modified attributes.
Notably, those due to modified doc comments.

Implementation:
- collect attributes during AST->HIR lowering, in `LocalDefId -> ItemLocalId -> &[Attributes]` nested tables;
- access the attributes through a `hir_owner_attrs` query;
- local refactorings to use this access;
- remove `attrs` from HIR data structures one-by-one.

Change in behaviour:
- the HIR visitor traverses all attributes at once instead of parent-by-parent;
- attribute arrays are sometimes duplicated: for statements and variant constructors;
- as a consequence, attributes are marked as used after unused-attribute lint emission to avoid duplicate lints.

~~Current bug: the lint level is not correctly applied in `std::backtrace_rs`, triggering an unused attribute warning on `#![no_std]`. I welcome suggestions.~~

compiler/rustc_resolve/src/late/lifetimes.rs

@@ -1239,7 +1239,8 @@ fn compute_object_lifetime_defaults(tcx: TyCtxt<'_>) -> HirIdMap<Vec<ObjectLifet
                 let result = object_lifetime_defaults_for_item(tcx, generics);
 
                 // Debugging aid.
-                if tcx.sess.contains_name(&item.attrs, sym::rustc_object_lifetime_default) {
+                let attrs = tcx.hir().attrs(item.hir_id());
+                if tcx.sess.contains_name(attrs, sym::rustc_object_lifetime_default) {
                     let object_lifetime_default_reprs: String = result
                         .iter()
                         .map(|set| match *set {