Add optional test macro arguments to allow for some of the tests to
depend on VTK_LARGE_DATA_ROOT and for most of the tests to have
their correct images in an pre-modularized vtkdata directory layout.
NOTE: This requires some VTKDATA file movement because old tests
have names like tname.cxx.png and this assumes tname.png.

Also make TestParallelRendering return some sort of pass/fail result.

Change-Id: Id76a92ac1d7f5eedb15baff91e6849b590961d5e