Fix transform of alpha and beta faces of TrapezoidVolumeBounds.
This MR fixes the transforms of two of the 6 surface representations of the trapezoid volume bounds (TrapezoidVolumeBounds_decomp.gif). Without this fix: with this fix: .
Also added unit test to check that the 8 corners of the trapezoid are on exactly 3 surface representations.
Edited by Goetz Gaycken