Revert "Mark two tests as expensive"

This reverts commit 1d952078c0.

test/lisp/calendar/todo-mode-tests.el

@@ -825,7 +825,6 @@ automatic testing."
 Calling todo-show should display the last current todo file, not
 necessarily the new file.  After deleting the new file, todo-show
 should display the previously current (or default) todo file."
-  :tags '(:expensive-test)
   (with-todo-test
    (todo-show)
    (should (equal todo-current-todo-file todo-test-file-1))

test/lisp/simple-tests.el

@@ -957,7 +957,6 @@ See Bug#21722."
 
 (ert-deftest simple-tests-shell-command-39067 ()
   "The output buffer is erased or not according to `shell-command-dont-erase-buffer'."
-  :tags '(:expensive-test)
   (let ((str "foo\\n"))
     (dolist (output-current '(t nil))
       (with-shell-command-dont-erase-buffer str output-current