Make abi::Abi Copy and remove a *lot* of refs

fix

fix

Remove more refs and clones

fix

more

fix

compiler/rustc_trait_selection/src/traits/object_safety.rs

@@ -465,9 +465,9 @@ fn virtual_call_violation_for_method<'tcx>(
 
             let param_env = tcx.param_env(method.def_id);
 
-            let abi_of_ty = |ty: Ty<'tcx>| -> Option<&Abi> {
+            let abi_of_ty = |ty: Ty<'tcx>| -> Option<Abi> {
                 match tcx.layout_of(param_env.and(ty)) {
-                    Ok(layout) => Some(&layout.abi),
+                    Ok(layout) => Some(layout.abi),
                     Err(err) => {
                         // #78372
                         tcx.sess.delay_span_bug(