org-fold-core-save-visibility: Fix macro expansion

* lisp/org-fold-core.el (org-fold-core-save-visibility): Calculate
folds on runtime, not during macro expansion.

* testing/lisp/test-org.el (test-org/org-ctrl-c-ctrl-c): Add test
ensuring that outline visibility is preserved upon refreshing Org
setup.

Reported-by: Matt Lundin <mdl@imapmail.org>
Link: https://orgmode.org/list/87wn70tlcn.fsf@fastmail.fm

lisp/org-fold-core.el

@@ -1063,7 +1063,7 @@ means that the buffer should stay alive during the operation,
 because otherwise all these markers will point to nowhere."
   (declare (debug (form body)) (indent 1))
   (org-with-gensyms (regions)
-    `(let* ((,regions ,(org-fold-core-get-regions :with-markers use-markers)))
+    `(let* ((,regions (org-fold-core-get-regions :with-markers ,use-markers)))
        (unwind-protect (progn ,@body)
          (org-fold-core-regions ,regions :override t :clean-markers t)))))
 

testing/lisp/test-org.el

@@ -3581,6 +3581,21 @@ SCHEDULED: <2017-05-06 Sat>
        (kill-buffer buffer))
      t)))
 
+(ert-deftest test-org/org-ctrl-c-ctrl-c ()
+  "Test `org-ctrl-c-ctrl-c' specifications."
+  ;; FIXME: Improve coverage.
+  ;; Preserve visibility after refreshing Org setup.
+  (org-test-with-temp-text
+      "#+TITLE: Test
+* Heading<point>
+text"
+    (org-overview)
+    (should (org-fold-folded-p (point) 'outline))
+    (save-excursion
+      (goto-char (point-min))
+      (org-ctrl-c-ctrl-c))
+    (should (org-fold-folded-p (point) 'outline))))
+
 
 ;;; Navigation