py3: avoid b'' output in test-hgweb-non-interactive.t

I couldn't figure out how to get the list to print without b'' with
pycompat.write(), without converted each element to str.

tests/test-hgweb-non-interactive.t

@@ -1,92 +1,96 b''
 Tests if hgweb can run without touching sys.stdin, as is required
 by the WSGI standard and strictly implemented by mod_wsgi.
 
   $ hg init repo
   $ cd repo
   $ echo foo > bar
   $ hg add bar
   $ hg commit -m "test"
   $ cat > request.py <<EOF
   > from __future__ import absolute_import
   > import os
   > import sys
   > from mercurial import (
   >     dispatch,
+  >     encoding,
   >     hg,
+  >     pycompat,
   >     ui as uimod,
   >     util,
   > )
   > ui = uimod.ui
   > from mercurial.hgweb.hgweb_mod import (
   >     hgweb,
   > )
   > stringio = util.stringio
   > 
   > class FileLike(object):
   >     def __init__(self, real):
   >         self.real = real
   >     def fileno(self):
   >         print >> sys.__stdout__, 'FILENO'
   >         return self.real.fileno()
   >     def read(self):
   >         print >> sys.__stdout__, 'READ'
   >         return self.real.read()
   >     def readline(self):
   >         print >> sys.__stdout__, 'READLINE'
   >         return self.real.readline()
   > 
   > sys.stdin = FileLike(sys.stdin)
   > errors = stringio()
   > input = stringio()
   > output = stringio()
   > 
   > def startrsp(status, headers):
   >     print('---- STATUS')
   >     print(status)
   >     print('---- HEADERS')
   >     print([i for i in headers if i[0] != 'ETag'])
   >     print('---- DATA')
   >     return output.write
   > 
   > env = {
   >     'wsgi.version': (1, 0),
   >     'wsgi.url_scheme': 'http',
   >     'wsgi.errors': errors,
   >     'wsgi.input': input,
   >     'wsgi.multithread': False,
   >     'wsgi.multiprocess': False,
   >     'wsgi.run_once': False,
   >     'REQUEST_METHOD': 'GET',
   >     'SCRIPT_NAME': '',
   >     'PATH_INFO': '',
   >     'QUERY_STRING': '',
   >     'SERVER_NAME': '$LOCALIP',
   >     'SERVER_PORT': os.environ['HGPORT'],
   >     'SERVER_PROTOCOL': 'HTTP/1.0'
   > }
   > 
   > i = hgweb(b'.')
   > for c in i(env, startrsp):
   >     pass
-  > print('---- ERRORS')
-  > print(errors.getvalue())
+  > sys.stdout.flush()
+  > pycompat.stdout.write(b'---- ERRORS\n')
+  > pycompat.stdout.write(b'%s\n' % errors.getvalue())
   > print('---- OS.ENVIRON wsgi variables')
   > print(sorted([x for x in os.environ if x.startswith('wsgi')]))
   > print('---- request.ENVIRON wsgi variables')
   > with i._obtainrepo() as repo:
-  >     print(sorted([x for x in repo.ui.environ if x.startswith(b'wsgi')]))
+  >     print(sorted([encoding.strfromlocal(x) for x in repo.ui.environ
+  >                   if x.startswith(b'wsgi')]))
   > EOF
   $ "$PYTHON" request.py
   ---- STATUS
   200 Script output follows
   ---- HEADERS
   [('Content-Type', 'text/html; charset=ascii')]
   ---- DATA
   ---- ERRORS
   
   ---- OS.ENVIRON wsgi variables
   []
   ---- request.ENVIRON wsgi variables
   ['wsgi.errors', 'wsgi.input', 'wsgi.multiprocess', 'wsgi.multithread', 'wsgi.run_once', 'wsgi.url_scheme', 'wsgi.version']
 
   $ cd ..