py3: drop b'' from generate-working-copy-states.py output

I could make everything bytes, but decoding filename seemed easier and we
don't have to worry about non-ascii filenames here.

contrib/python3-whitelist

@@ -200,6 +200,7 b' test-merge-closedheads.t'
 test-merge-commit.t
 test-merge-criss-cross.t
 test-merge-default.t
+test-merge-force.t
 test-merge-internal-tools-pattern.t
 test-merge-local.t
 test-merge-remove.t

tests/generate-working-copy-states.py

@@ -66,7 +66,7 b' combinations = sorted(generatestates(max'
 content = []
 for filename, states in combinations:
     if target == 'filelist':
-        print(filename)
+        print(filename.decode('ascii'))
     elif target == 'state':
         if depth == 'wc':
             # Make sure there is content so the file gets written and can be