In some situations where two beveled edges were very close to in-line
but not quite straight, bevel would build a miter when it shouldn't.
The code that chose whether to use a miter at each vertex was slightly
incorrect.
For outer miters there is a check for 3 or more selected edges, but an
inner miter can still be useful with only two beveled edges at a vertex,
so we can't use that here. Instead I changed the check for in-line edges
to run before determining whether the angle is reflex or not. The logic
ends up a bit more straightforward as well. This doesn't completely
remove the rather strange looking triangle vertex meshes at each corner,
but it does make it stable when locations are slightly adjusted.
The only other place this `edges_angle_kind` function was used is for
profile=1.0 vertex meshes. I tested and made sure that still works well.
Differential Revision: https://developer.blender.org/D9420
c6d8300823