Add test also to test_syntax

Author: pablogsal

Lib/test/test_syntax.py

@@ -659,6 +659,9 @@
     Traceback (most recent call last):
     SyntaxError: cannot assign to __debug__
 
+    >>> import ä £
+    Traceback (most recent call last):
+    SyntaxError: invalid character '£' (U+00A3)
 """
 
 import re