Moved Unicode C API related tests to separate test class.

diff --cc Lib/test/test_unicode.py
index 2684b940ef5c7e626acd20d318e313e51bd30623,082f6b59da36edc5e09aa3674b47a9247a6f56cc..9cb69d486212eb317c43fe745bb70c2542e311bb
--- 1/Lib/test/test_unicode.py
--- 2/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@@ -2749,16 -2732,6 +2756,12 @@@ class CAPITest(unittest.TestCase)
                  # Check that the second call returns the same result
                  self.assertEqual(getargs_s_hash(s), chr(k).encode() * (i + 1))
  
-     def test_free_after_iterating(self):
-         support.check_free_after_iterating(self, iter, str)
-         support.check_free_after_iterating(self, reversed, str)
- 
 +    def test_invalid_sequences(self):
 +        for letter in string.ascii_letters + "89": # 0-7 are octal escapes
 +            if letter in "abfnrtuvxNU":
 +                continue
 +            with self.assertWarns(DeprecationWarning):
 +                eval(r"'\%s'" % letter)
  
  class StringModuleTest(unittest.TestCase):
      def test_formatter_parser(self):