Auto merge of #108006 - cjgillot:def-impl, r=oli-obk

Avoid accessing HIR when it can be avoided

Experiment to see if it helps some incremental cases.

Will be rebased once https://github.com/rust-lang/rust/pull/107942 gets merged.

r? `@ghost`

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -987,7 +987,7 @@ impl<'a, 'b, 'tcx> BuildReducedGraphVisitor<'a, 'b, 'tcx> {
                 | DefKind::LifetimeParam
                 | DefKind::GlobalAsm
                 | DefKind::Closure
-                | DefKind::Impl
+                | DefKind::Impl { .. }
                 | DefKind::Generator,
                 _,
             )