Ignore startup file in test_dumb_terminal_exits_cleanly

Author: bswck

Lib/test/test_pyrepl/test_pyrepl.py

@@ -1406,6 +1406,7 @@ class TestDumbTerminal(ReplTestCase):
     def test_dumb_terminal_exits_cleanly(self):
         env = os.environ.copy()
         env.pop('PYTHON_BASIC_REPL', None)
+        env.pop('PYTHONSTARTUP', None)
         env.update({"TERM": "dumb"})
         output, exit_code = self.run_repl("exit()\n", env=env)
         self.assertEqual(exit_code, 0)