Issue #7449, last part (11): fix many tests if thread support is disabled

 * Use try/except ImportError or test_support.import_module() to import thread
   and threading modules
 * Add @unittest.skipUnless(threading, ...) to testcases using threads
diff --git a/Lib/test/test_thread.py b/Lib/test/test_thread.py
index 33109ec..544e70d 100644
--- a/Lib/test/test_thread.py
+++ b/Lib/test/test_thread.py
@@ -2,7 +2,7 @@
 import unittest
 import random
 from test import test_support
-import thread
+thread = test_support.import_module('thread')
 import time
 import sys
 import weakref