bpo-14117: Make minor tweaks to turtledemo (GH-8002)

The 'wikipedia' example is now 'rosette', describing what it draws.
The 'penrose' print output is reduced.  The 'tree' '1024'
output is eliminated.

Lib/turtledemo/tree.py

@@ -49,7 +49,6 @@ def maketree():
     t = tree([p], 200, 65, 0.6375)
     for x in t:
         pass
-    print(len(p.getscreen().turtles()))
 
 def main():
     a=clock()