macro expander: fix #%top via local-expand

Fix bug in b25a2b83ba that breaks the teaching languages.

pkgs/racket-pkgs/racket-test/tests/racket/macro.rktl

@@ -1085,6 +1085,14 @@
                      (error 'test "bad expansion: ~e" e)]))])
   (m))
 
+(test 10 values
+      (let-syntax ([#%top (lambda (stx)
+                            (syntax-case stx ()
+                              [(_ . id) #'10]))])
+        (let-syntax ([m (lambda (stx)
+                          (local-expand #'nonsuch 'expression null))])
+          (m))))
+
 ;; ----------------------------------------
 
 (report-errs)

racket/src/racket/src/compile.c

@@ -4817,6 +4817,7 @@ scheme_compile_expand_expr(Scheme_Object *form, Scheme_Comp_Env *env,
     } else {
       if (!rec[drec].comp
           && (rec[drec].depth == -2) /* local-expand */
+          && SAME_OBJ(var, normal)
           && SAME_OBJ(SCHEME_STX_VAL(stx), top_symbol)) {
         rec[drec].pre_unwrapped = 1;
       } else {