Convert bugs back to delayed_bugs.

This commit undoes some of the previous commit's mechanical changes,
based on human judgment.

compiler/rustc_resolve/src/late.rs

@@ -3681,9 +3681,9 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
                 None
             }
             Res::SelfCtor(_) => {
-                // njn: remove comment?
                 // We resolve `Self` in pattern position as an ident sometimes during recovery,
-                // so delay a bug instead of ICEing.
+                // so delay a bug instead of ICEing. (Note: is this no longer true? We now ICE. If
+                // this triggers, please convert to a delayed bug and add a test.)
                 self.r.dcx().span_bug(
                     ident.span,
                     "unexpected `SelfCtor` in pattern, expected identifier"