Issue #20557: Use specific asserts in io tests.

diff --cc Lib/test/test_fileio.py
index 0f8310ce2b6fa64ca3284218082c094a33185c5b,a4fd20dcf242c3d2803022bb4b7bac54740e4fe0..59cc38f6ca2dfa617aa63d96b1dccf1b898c782d
--- 1/Lib/test/test_fileio.py
--- 2/Lib/test/test_fileio.py
+++ b/Lib/test/test_fileio.py
@@@ -183,9 -119,9 +183,9 @@@ class AutoFileTests
          self.assertRaises(ValueError, f.read, 10) # Open for reading
          f.close()
          self.assertTrue(f.closed)
 -        f = _FileIO(TESTFN, 'r')
 +        f = self.FileIO(TESTFN, 'r')
          self.assertRaises(TypeError, f.readinto, "")
-         self.assertTrue(not f.closed)
+         self.assertFalse(f.closed)
          f.close()
          self.assertTrue(f.closed)
  

diff --cc Lib/test/test_io.py
Simple merge

diff --cc Lib/test/test_memoryio.py
Simple merge