test_httpservers: Python CGI scripts have to be encoded to utf-8
test_httpservers: Python CGI scripts have to be encoded to utf-8

And not the locale encoding. With this commit, the test finally pass on Windows
with a non-ascii path :-)

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator