gh-88496: Fix IDLE test hang on macOS (#104025)

Replace widget.update() with widget.update_idletasks in two places.

Lib/idlelib/colorizer.py

@@ -310,7 +310,7 @@ class ColorDelegator(Delegator):
                     # crumb telling the next invocation to resume here
                     # in case update tells us to leave.
                     self.tag_add("TODO", next)
-                self.update()
+                self.update_idletasks()
                 if self.stop_colorizing:
                     if DEBUG: print("colorizing stopped")
                     return

Lib/idlelib/outwin.py

@@ -112,7 +112,7 @@ class OutputWindow(EditorWindow):
         assert isinstance(s, str)
         self.text.insert(mark, s, tags)
         self.text.see(mark)
-        self.text.update()
+        self.text.update_idletasks()
         return len(s)
 
     def writelines(self, lines):

Misc/NEWS.d/next/IDLE/2023-04-30-20-01-18.gh-issue-88496.y65vUb.rst

@@ -0,0 +1 @@
+Fix IDLE test hang on macOS.