Run 2to3 tests.

Lib/test/test_lib2to3.py

+# Skipping test_parser and test_all_fixers
+# because of running
+from lib2to3.tests import test_fixers, test_pytree, test_util
+import unittest
+from test.test_support import run_unittest
+
+def suite():
+    tests = unittest.TestSuite()
+    loader = unittest.TestLoader()
+    for m in (test_fixers,test_pytree,test_util):
+        tests.addTests(loader.loadTestsFromModule(m))
+    return tests
+
+def test_main():
+    run_unittest(suite())