macro-stepper: fix value of absent evaluations (local actions) on error

related to PR 12316

collects/macro-debugger/model/deriv-parser.rkt

@@ -118,6 +118,7 @@
     ;; Evaluation
     ;; Answer = (listof LocalAction)
     (Eval
+     (#:skipped null)
      [((? LocalActions)) $1])
 
     ;; Prepare env for compilation

collects/macro-debugger/model/reductions.rkt

@@ -221,7 +221,7 @@
 
     [(Wrap p:provide (e1 e2 rs ?1 inners ?2))
      (let ([wrapped-inners
-            (for/list ([inner inners])
+            (for/list ([inner (in-list inners)])
               (match inner
                 [(Wrap deriv (e1 e2))
                  (make local-expansion e1 e2