Use bigmemtest decorator for test of issue #16335.

diff --cc Lib/test/test_ucn.py
index 05557ae55f6f09680febc4fc443032dcd107eb1c,6fae421f3e33c3a0ae4e23a05a419e262d0c7b1a..f949761ab38c326374e7883d8a58e801bc87356d
--- 1/Lib/test/test_ucn.py
--- 2/Lib/test/test_ucn.py
+++ b/Lib/test/test_ucn.py
@@@ -218,18 -144,17 +218,17 @@@ class UnicodeNamesTest(unittest.TestCas
  
      @unittest.skipUnless(_testcapi.INT_MAX < _testcapi.PY_SSIZE_T_MAX,
                           "needs UINT_MAX < SIZE_MAX")
-     def test_issue16335(self):
+     @support.bigmemtest(size=_testcapi.UINT_MAX + 1,
 -                        memuse=1 + 4 // len('\U00010000'), dry_run=False)
++                        memuse=1 + 1, dry_run=False)
+     def test_issue16335(self, size):
          # very very long bogus character name
-         try:
-             x = b'\\N{SPACE' + b'x' * (_testcapi.UINT_MAX + 1) + b'}'
-             self.assertEqual(len(x), len(b'\\N{SPACE}') +
-                                      (_testcapi.UINT_MAX + 1))
-             self.assertRaisesRegex(UnicodeError,
-                 'unknown Unicode character name',
-                 x.decode, 'unicode-escape'
-             )
-         except MemoryError:
-             raise unittest.SkipTest("not enough memory")
+         x = b'\\N{SPACE' + b'x' * (_testcapi.UINT_MAX + 1) + b'}'
+         self.assertEqual(len(x), len(b'\\N{SPACE}') +
+                                     (_testcapi.UINT_MAX + 1))
+         self.assertRaisesRegex(UnicodeError,
+             'unknown Unicode character name',
+             x.decode, 'unicode-escape'
+         )
  
  
  def test_main():