Fixed issue in filter leading to sanitizer errors.

vtkDataSetSurfaceFilter had some funky code designed to optimize
(minimize) allocation of small objects. This required apparently
writing beyond the limits of an array. It was not a bug but made
tools like the clang sanitizer think that it was. Fixed it while
still maintaining the allocation optimization, at the cost of a
bit more memory usage.

Change-Id: I3ef7051e85601a4440f02cb4dfe2e15227a06e87
Merge topic 'dataset-surface-fix' into master

3978a87e Fixed issue in filter leading to sanitizer errors.