bpo-30843: Rename Lib/test/bisect.py to Lib/test/bisectcmd.py (#2563)

Revert test_bisect.py change:
remove "from __future__ import absolute_import".

Lib/test/test_bisect.py

-# Use absolute import to prevent importing Lib/test/bisect.py,
-# instead of Lib/bisect.py
-from __future__ import absolute_import
-
 import sys
 import unittest
 from test import test_support