Views/Infovis: Add another baseline for TestConeLayoutStrategy

The Mesa Gallium 'swrast' driver combines pixel-wide overlapping lines
differently, but validly.  Add a baseline representing its result.

Change-Id: I31973e8a6b6776fdb322f6efa8c09b3ac9446525
Merge topic 'vtkViewsInfovisCxx-TestConeLayoutStrategy-baseline' into master

5782e17b Views/Infovis: Add another baseline for TestConeLayoutStrategy