Adjusts behavior for trimming Bezier curves, specifically the outer
Bezier handles for the endpoints which do not influence the actual
curve. Handles are only adjusted if they lie within the same segment
with at most one endpoint being a control point (unless they are the
same in which handles are set to the point itself). The result yields
a curve in which the trim result can be inverted by re-setting the
cyclic property for the curve using 'Set Spline Cyclic' node
(iff both trim endpoints lie within a segment).
Differential Revision: https://developer.blender.org/D16488
b28348f9e9