Allow skipping of regression tests not supported on windows. This reduces noise…

Allow skipping of regression tests not supported on windows.  This reduces noise in the regression test suite for py3k on Windows.

Lib/test/regrtest.py

@@ -892,6 +892,7 @@ _expectations = {
         test_fork1
         test_epoll
         test_dbm_gnu
+        test_dbm_ndbm
         test_grp
         test_ioctl
         test_largefile

Lib/test/test_dbm_gnu.py

-import dbm.gnu as gdbm
+from test import support
+gdbm = support.import_module("dbm.gnu") #skip if not supported
 import unittest
 import os
 from test.support import verbose, TESTFN, run_unittest, unlink

Lib/test/test_dbm_ndbm.py

 from test import support
+support.import_module("dbm.ndbm") #skip if not supported
 import unittest
 import os
 import random

Lib/test/test_posix.py

 "Test posix functions"
 
 from test import support
+posix = support.import_module('posix') #skip if not supported
 
 import time
 import os
@@ -9,8 +10,6 @@ import shutil
 import unittest
 import warnings
 
-posix = support.import_module('posix')
-
 warnings.filterwarnings('ignore', '.* potential security risk .*',
                         RuntimeWarning)
 

Lib/test/test_pty.py

+from test import support
+pty = support.import_module("pty") #skip if not supported
 import errno
 import fcntl
-import pty
 import os
 import sys
 import signal

Lib/test/test_syslog.py

 
-import syslog
-import unittest
 from test import support
+syslog = support.import_module("syslog") #skip if not supported
+import unittest
 
 # XXX(nnorwitz): This test sucks.  I don't know of a platform independent way
 # to verify that the messages were really logged.

Lib/test/test_tk.py

+from test import support
+# Skip test if _tkinter wasn't built.
+support.import_module('_tkinter')
+
 import tkinter
 from tkinter.test import runtktests
-from test import support
 import unittest
 
-# Skip test if _tkinter wasn't built.
-support.import_module('_tkinter')
 
 import tkinter