[3.8] gh-97032: avoid test_squeezer crash on macOS buildbots (GH-115508…

…) (GH-115656)

(cherry picked from commit 17a6533)

Co-authored-by: Ned Deily <nad@python.org>

Lib/idlelib/idle_test/test_squeezer.py

@@ -171,6 +171,7 @@ def test_write_not_stdout(self):
 
     def test_write_stdout(self):
         """Test Squeezer's overriding of the EditorWindow's write() method."""
+        requires('gui')
         editwin = self.make_mock_editor_window()
 
         for text in ['', 'TEXT']: