Add import_function method to test.test_support, and modify a number of

tests that expect to be skipped if imports fail or functions don't
exist to use import_function and import_module.  The ultimate goal is
to change regrtest to not skip automatically on ImportError.  Checking
in now to make sure the buldbots don't show any errors on platforms
I can't direct test on.

Lib/test/test_winreg.py

@@ -1,12 +1,15 @@
 # Test the windows specific win32reg module.
 # Only win32reg functions not hit here: FlushKey, LoadKey and SaveKey
 
-from _winreg import *
 import os, sys
 import unittest
-
 from test import test_support
 
+#Do this first so test will be skipped if module doesn't exist
+test_support.import_module('_winreg')
+#Now import everything
+from _winreg import *
+
 test_key_name = "SOFTWARE\\Python Registry Test Key - Delete Me"
 
 test_data = [