[PATCH 2 of 5] py3: add a missing b'' for Windows

[Matt Harbison]

# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1537324803 14400
#      Tue Sep 18 22:40:03 2018 -0400
# Node ID b99b91e41ae278b503c91895068cd10e0d0a429a
# Parent  6cf61fcd3fad06f14668a4cc56cc7c5351561219
py3: add a missing b'' for Windows

I tried ./contrib/byteify-strings.py, but there were way too many changes (and
most looked wrong).  This was hit with test-check-interfaces.py.

# skip-blame for b'' prefixes

diff --git a/tests/run-tests.py b/tests/run-tests.py
--- a/tests/run-tests.py
+++ b/tests/run-tests.py
@@ -1211,7 +1211,7 @@ class Test(unittest.TestCase):
             output = re.sub(s, r, output)
 
         if normalizenewlines:
-            output = output.replace('\r\n', '\n')
+            output = output.replace(b'\r\n', b'\n')
 
         return ret, output.splitlines(True)