BUG: Increase itkVoronoiPartitioningImageFilterTest1 for 32-bit builds.

Change-Id: Ia1c9b803664693a37aa28872ae09a8ef79a02c28
Merge topic 'voronoi'

76c45806 BUG: Increase itkVoronoiPartitioningImageFilterTest1 for 32-bit builds.