Add new todo-mode.el tests

Add new todo-mode.el tests

* test/lisp/calendar/todo-mode-tests.el (with-todo-test):
Declare an Edebug spec.  Restore pre-test-run state of test files.
(todo-test--show, todo-test--move-item)
(todo-test--insert-item): New functions.
(todo-test-get-archive): Remove, as subsumed by
todo-test--show.  Adjust all callers.
(todo-test--is-current-buffer): Rename from
todo-test-is-current-buffer and adjust uses.
(todo-test-item-highlighting): Use todo-test--show.
(todo-test-revert-buffer01, todo-test-revert-buffer02)
(todo-test-raise-lower-priority)
(todo-test-todo-mark-unmark-category, todo-test-move-item01)
(todo-test-move-item02, todo-test-move-item03)
(todo-test-move-item04, todo-test-move-item05)
(todo-test-toggle-item-header01)
(todo-test-toggle-item-header02)
(todo-test-toggle-item-header03)
(todo-test-toggle-item-header04)
(todo-test-toggle-item-header05)
(todo-test-toggle-item-header06)
(todo-test-toggle-item-header07): New tests.

* test/lisp/calendar/todo-mode-resources/todo-test-1.toda:
* test/lisp/calendar/todo-mode-resources/todo-test-1.todo:
Modify to accommodate new tests.