refactor: remove unneeded backward.py shims

Removed were:

- StringIO
- configparser
- string_class
- unicode_class
- range
- zip_longest
- get_thread_id
- path_types
- shlex_quote
- reprlib

1 files changed, 3 insertions, 2 deletions

diff --git a/coverage/debug.py b/coverage/debug.py
index 194f16f5..efcaca2a 100644
--- a/coverage/debug.py
+++ b/coverage/debug.py
@@ -6,16 +6,17 @@
 import contextlib
 import functools
 import inspect
+import io
 import itertools
 import os
 import pprint
+import reprlib
 import sys
 try:
     import _thread
 except ImportError:
     import thread as _thread
 
-from coverage.backward import reprlib, StringIO
 from coverage.misc import isolate_module
 
 os = isolate_module(os)
@@ -86,7 +87,7 @@ class DebugControl(object):
 class DebugControlString(DebugControl):
     """A `DebugControl` that writes to a StringIO, for testing."""
     def __init__(self, options):
-        super(DebugControlString, self).__init__(options, StringIO())
+        super(DebugControlString, self).__init__(options, io.StringIO())
 
     def get_output(self):
         """Get the output text from the `DebugControl`."""