Test attribute access on non-global names

(I'm improving branch coverage.)

tests/dotted-names.txt

@@ -12,6 +12,7 @@ expressions.  It works with dotted names too:
     ... def f2():
     ...     import os.path
     ...     os.path.exists('foo')
+    ...     x[0].append('')
     ... ''')
 
     >>> imports, unused_names = find_imports_and_track_names('marmalade.py')