test-ob-fortran: re-enable formerly failing test

* testing/lisp/test-ob-fortran.el (ob-fortran/character-var):
  Uncomment test that formerly failed.

This test seems to be working correctly on Linux and Cygwin.
Re-enable to see if it may not work on other systems and then check
why.

testing/lisp/test-ob-fortran.el

@@ -50,12 +50,11 @@
     (org-babel-next-src-block 2)
     (should (= 42 (org-babel-execute-src-block)))))
 
-;; ;; TODO: test fails
-;; (ert-deftest ob-fortran/character-var ()
-;;   "Test string input"
-;;   (org-test-at-id "d8d1dfd3-5f0c-48fe-b55d-777997e02242"
-;;     (org-babel-next-src-block 3)
-;;     (should (equal "word" (org-babel-execute-src-block)))))
+(ert-deftest ob-fortran/character-var ()
+  "Test string input"
+  (org-test-at-id "d8d1dfd3-5f0c-48fe-b55d-777997e02242"
+    (org-babel-next-src-block 3)
+    (should (equal "word" (org-babel-execute-src-block)))))
 
 (ert-deftest ob-fortran/list-var ()
   "Test real array input"