CurvatureAnisotropicDiffusionImageFilterTest failures

@seanm

The CurvatureAnisotropicDiffusionImageFilterTest and LaplacianSharpeningImageFilterTest differences do not look significant to me.

I think I have seem similar Resampling differences with that test. As I recall this is with the nearest neighbor interpolator, which is numerically problematic when the expected value is close to a rounding boundary. This discourse thread may shed some light: