I've been handling this wrong. Fixed in changeset:   6422:91ae685405ba

I fixed templating.py:history(). It should always use only the
database values, so set self._client.form_wins to False for the
duration of the method. Set to original value on return.

This replaces a ton of changes to templates. That was the wrong way
to "fix" this.

Also for the record modifying:

 templating/engine_jinja2.py Jinja2Loader::__init__

 to use:

   extensions=['jinja2.ext.i18n', 'jinja2.ext.do']

makes:

  {% do utils.set_form_wins(request.client, False) %}

work as expected producing no output.

Christof, should we add some other jinja2 extensions or expose it
via the config.ini mechanism? This extension seems to mimic the
tal:omit-tag attribute.

Again this change falls into the black hole in the test framework.
So marked NeedsTesting.