Issue #13183: Revert 0b53b70a40a0 (reenable test on windows)

Lib/test/test_pdb.py

 # A test suite for pdb; not very comprehensive at the moment.
-import os
+
 import imp
 import pdb
 import sys
@@ -631,7 +631,6 @@ class PdbTestCase(unittest.TestCase):
         self.assertNotIn(b'SyntaxError', stdout,
                          "Got a syntax error running test script under PDB")
 
-    @unittest.skipIf(os.name == 'nt', "temporarily disabled on Windows")
     def test_issue13183(self):
         script = """
             from bar import bar