refactor: remove more unneeded backward.py shims

Gone are:

- iitems
- litems
- iternext
- to_bytes
- to_string
- binary_bytes
- byte_to_int
- bytes_to_ints
- BUILTINS

1 files changed, 2 insertions, 3 deletions

diff --git a/coverage/phystokens.py b/coverage/phystokens.py
index 7556d310..4b69c476 100644
--- a/coverage/phystokens.py
+++ b/coverage/phystokens.py
@@ -8,7 +8,6 @@ import re
 import token
 import tokenize
 
-from coverage.backward import iternext
 from coverage.misc import contract
 
 
@@ -140,7 +139,7 @@ class CachedTokenizer(object):
         """A stand-in for `tokenize.generate_tokens`."""
         if text != self.last_text:
             self.last_text = text
-            readline = iternext(text.splitlines(True))
+            readline = iter(text.splitlines(True)).__next__
             self.last_tokens = list(tokenize.generate_tokens(readline))
         return self.last_tokens
 
@@ -159,7 +158,7 @@ def source_encoding(source):
     Returns a string, the name of the encoding.
 
     """
-    readline = iternext(source.splitlines(True))
+    readline = iter(source.splitlines(True)).__next__
     return tokenize.detect_encoding(readline)[0]