Partial py3k-ification of Doc/library/: convert has_key references into either 'k in d' or __contains__; normalize raise statements; convert print statements into print function calls.

Doc/library/test.rst

@@ -307,7 +307,7 @@ The :mod:`test.test_support` module defines the following functions:
    Example use::
 
       with captured_stdout() as s:
-          print "hello"
+          print("hello")
       assert s.getvalue() == "hello"