Remove unused imports in tests (GH-14518)

diff --git a/Lib/test/test_codeccallbacks.py b/Lib/test/test_codeccallbacks.py
index 585992b..243f002 100644
--- a/Lib/test/test_codeccallbacks.py
+++ b/Lib/test/test_codeccallbacks.py
@@ -1,10 +1,10 @@
 import codecs
 import html.entities
 import sys
-import test.support
 import unicodedata
 import unittest
 
+
 class PosReturn:
     # this can be used for configurable callbacks