'ForNode.render() pops the values it pushes to the context (#28001).'

@setup({'main': '{%    with    alpha=alpha.values    %}{%    include    "base"    %}{%    endwith    %}_{%    with    alpha=alpha.extra    %}{%    include    "base"    %}{%    endwith    %}', 'base': '{%    for    x,    y    in    alpha    %}{{    x    }}:{{    y    }},{%    endfor    %}'})
def test_for_tag_context(self):

    output = self.engine.render_to_string('main', {'alpha': {'values': [('two', 2), ('four', 4)], 'extra': [('six', 6), ('eight', 8)]}})
    self.assertEqual(output, 'two:2,four:4,_six:6,eight:8,')
