ENH: Restore Imaging/Core tests

1) Restore tests that were skipped during modularization
2) Modernize the tests to use vtkNew or vtkSmartPointer
3) Use RENDERING_FACTORY for the tests

Change-Id: Ibfc8cdc6437760bf8a2069df047ac1bad56e41fd
Merge topic 'RestoreImagingCoreTests' into master

ecf4fb43 ENH: Restore Imaging/Core tests