test_posix is an expected skip on Win32. Also fixed test_posix to

import from test.test_support instead of directly from test_support.

Lib/test/regrtest.py

@@ -572,6 +572,7 @@ _expectations = {
         test_openpty
         test_ossaudiodev
         test_poll
+        test_posix
         test_pty
         test_pwd
         test_resource

Lib/test/test_posix.py

 "Test posix functions"
 
-from test_support import TestSkipped, TestFailed, TESTFN, run_suite
+from test.test_support import TestSkipped, TestFailed, TESTFN, run_suite
 
 try:
     import posix