With such small proxy sizes (combined with a small blur radius), the
kernels `halfWidth` can get zero, which leads to a memory allocation of
same zero size and writing to that memory leads to overflow/crashes/can
only go downhill from there.
Now early out in such cases [which leads to
slightly different output -- well if the "buggy" output survives and
does not crash that is].
(alternatively we could just prevent the overflow and still let do
`RVBlurBitmap2_float` do stuff that it really shouldnt imo, see first version of the PR)
Pull Request: https://projects.blender.org/blender/blender/pulls/111660
f77fdbff8a